How to grow gladiolus? Summer flower cultivation and care tips

Gladiolus is a flower with dazzling, gorgeous colors. Its flowering period falls in summer, and its blooms are beautiful. It can be planted in courtyards or in pots, and can also be used as cut flowers for bouquets. It has excellent ornamental value. Below are detailed cultivation tips for gladiolus; friends who love flowers and plants can save them.

Environment

Gladiolus is a long-day plant. It likes a sunny, cool environment, is not tolerant of cold or heat, and prefers a climate with warm winters and cool summers.

Soil

Gladiolus likes loose, fertile, moist, well-drained sandy soil. For potting, garden soil, plant ash and river sand can be mixed.

Temperature

The suitable growth temperature for gladiolus is 20-25 degrees. If the temperature is too high, water should be sprinkled promptly to cool it down, otherwise growth will be harmed.

Sunlight

During the growing season, gladiolus grows robustly and has brightly colored flowers with sufficient sunlight. With insufficient light, it blooms less. After flower bud differentiation, short-day conditions can help advance the flowering period.

Watering

During the growing period, gladiolus should not be watered too much; water thoroughly when the soil is dry. Too much water will make the plant grow leggy and lodge, and will also affect the number of flowers. It is not tolerant of waterlogging, so in the rainy season, drainage should be timely; waterlogging will rot the corms.

Fertilizing

Gladiolus likes fertilizer. During the growing period, a phosphorus-potassium fertilizer should be applied once a month, which benefits the cormlets, growth and flower bud differentiation. Phosphorus fertilizer can improve flower quality. Water and fertilizer should not be too concentrated, otherwise the plant will grow leggy.

The greatest feature of gladiolus is its beautiful flower form, and it is also easy to cultivate. However, when planting, attention should be paid to the planting environment and temperature. The above are cultivation methods for gladiolus; you can try planting them.

Gladiolus planting and cultivation methods

Flower Bonsai Network Flower Care Column: Gladiolus planting and cultivation methods

Flower profile:Gladiolus, also known as changpu, jianlan, bianzhulian, shisantai bao, chanlan, and shiyangjin, is a perennial herbaceous flower of the genus Gladiolus in the family Iridaceae.

Gladiolus flower language:Festive, auspicious, attentive, relaxed, rising step by step.

Growing areas: the Cape of Good Hope in Africa, the Mediterranean coast and West Asia. In China, gladiolus cultivation is mainly distributed in Jilin, Liaoning, Gansu, Wuhan, Baotou and other places.

Benefits of growing flowers:Gladiolus can be used to monitor fluoride. As long as there is one part per billion of harmful gas in the air, this plant will show dry and withered leaves. The gladiolus flower stalk is upright and slender, with many flowers and bright colors. It is one of the famous cut flower materials, known as the "king of cut flowers." It can be used for bouquets and flower baskets, and can also decorate doorways. Its corms have the effects of clearing heat and detoxifying, activating blood and dispersing stasis, and reducing swelling and relieving pain. Fresh corms can be mashed into juice and applied externally to treat carbuncles and mumps.

Flowers and leaves:The plant height is 90-150 cm. The stem is thick, upright, and seldom branched. The leaves are sword-shaped, hard in texture, with prominent parallel veins. The flower stem rises above the leaves. The spike inflorescence bears 12-24 flowers in two rows, facing to one side. The corolla tube is an enlarged funnel shape, slightly curved upward.

Variety selection:The main cultivated varieties include Lanyu, Mascagni, Qinggu Hong, European Dream, Hua Rose, Sachsen, Supreme Rose, Nova, Priscilla, Loyalty, etc.

Plant selection:Generally, small corms of the flat-round type that are disease-free, spot-free, and have no damage to the sprouting and rooting parts are selected for cultivation. Generally, high-quality seed corms have a relatively large ratio of thickness to diameter, feel heavy, and feel very hard rather than soft to the touch. The surface of the corm is flat and smooth, with no large depression in the middle. The bud points are convex and plump.

Flower pot selection: clay pot.

Preparation of growing soil:

Gladiolus does not have high soil requirements. It is best to choose loose, fertile, humus-rich, highly permeable, slightly acidic sandy soil, with a pH preferably between 5.6 and 6.5.
Preparation method 1: Mix mature soil and leaf mold at 4:1, then add two spoonfuls of compound fertilizer and mix.

Preparation method 2: Mix loam and leaf mold at 2:1, then add base fertilizer such as cow manure and mix.

Flower cultivation:

Planting is generally done in April. First block the drainage hole at the bottom of the pot with a tile, then place some coarse growing soil at the bottom of the pot, then add finer growing soil, place the corm upright in the exact center, and then press the surrounding growing soil firmly to prevent the corm from being crooked, which would make the grown plant crooked and affect its appearance. Finally, the top of the corm should be slightly exposed above the soil surface. Note here that gladiolus roots do not grow straight down but often grow horizontally, so when potting, the corm should be placed deeper, with a depth of about 12 cm being most suitable, to prevent lodging after the plant grows.

After planting, water thoroughly, then keep the potting soil moist, but do not let water accumulate in the pot. Place it in a ventilated, sunny place. After about 8 weeks, the corm will sprout. When the sprout color gradually turns green, it can be exposed to sunlight. After the flower stem emerges, water can be sprayed on the leaves to keep the potting soil moist, and dilute liquid fertilizer can be applied. Fertilization must be even; too much fertilizer will make the plant lodge. Generally, fertilize once when the plant has grown two leaves, once at the bud stage, and once after flowering.

About one month after flowering, after the leaves turn yellow, the corms can be dug out, the withered upper leaves cut off, and the new corms and cormlets separated. After drying in the sun, store them in a ventilated, dry place at 5°C-10°C until planting the next year.

Fertilizing: When planting, to ensure sufficient nutrients for plant growth and development, sufficient base fertilizer should be applied. Applying decomposed organic fertilizer is best.

However, gladiolus does not like heavy fertilizer and is a shallow-rooted plant, so fertilizer should be applied shallowly and lightly.

During its growing period, fertilizer should be applied as a top dressing 3 times. The first time is after 2 leaves have unfolded. A dilute liquid fertilizer containing more nitrogen fertilizer should be applied, such as decomposed organic fertilizer. Because flower bud differentiation begins at this time, if fertilizer is lacking, the number of flowers will decrease.

The second time is applied after the 4th leaf emerges. At this time the plant is at the bud stage, and a dilute liquid fertilizer mainly of phosphorus-potassium fertilizer should be applied, which can promote thick and strong flower stems and large flowers. To make the flower colors bright, apply superphosphate and bone meal once together with watering. After the flower scape grows, a 1% superphosphate solution can be sprayed on the aboveground part.

The third time is after flowering. To promote the development of new corms, more phosphorus-potassium fertilizer should be applied and less nitrogen fertilizer. If nitrogen fertilizer is excessive, it will cause the seed corms to rot.
Watering: Gladiolus is a flower that needs more water. Timely watering and keeping the soil moist are important measures to promote more flowering.

Generally, after seedlings emerge, water once every 2-3 days; in summer, water once every 1-2 days. After the flower scape emerges and buds appear, water frequently to ensure sufficient moisture; you can water once a day and provide slight shading. In the rainy season, drain water promptly.

In spring, when there is a lot of rain and humidity is high, before the plant grows 3 leaves, watering should be appropriately controlled and done only when the soil is dry, which can promote root growth.
If hot, high temperatures occur, spray promptly to increase humidity and lower the temperature.

From October onward, watering should be stopped.

Gladiolus pruning:

Gladiolus usually does not require shaping or pruning, but after the flower scape grows, if it lodges due to rain, it should be propped up promptly; otherwise it will bend and grow underground, and once it bends and grows, it cannot return to its original state.

Light and temperature management: Gladiolus is not shade-tolerant and is a light-loving, long-day plant. It must receive no less than 12 hours per day, with 16 hours of light being most suitable.

Long-day and strong light conditions favor flower bud development. If, when it has grown 4-5 leaves, the light duration is reduced and light intensity lowered, its flowering rate will decline significantly.

And if the sunshine duration is too short, gladiolus is prone to wilt disease.

In winter, under short-day or weak-light conditions, supplementary artificial light is needed. Daily light duration must not be less than 12 hours, with 16 hours being best. Cut flower varieties are greatly affected by light; sufficient sunlight makes them grow robustly, with strong stress resistance, and bright, long-lasting flower colors. But in hot summer, direct strong sunlight should also be avoided.

The suitable growth temperature is 20-25°C during the day and 10°C-15°C at night. When the temperature is above 27°C, plant growth is hindered and petals are easily scorched. When the temperature is below 10°C, plant growth is slow. The minimum growth temperature is 5°C; below 3°C growth stops. If the temperature drops to 0°C, the plant will freeze to death.

Gladiolus flowering and fruiting period management:

The natural flowering period of gladiolus is in spring or summer. Generally, appropriately increasing light in winter will help flowering and improve flower quality; appropriately shading flowers in summer and lowering the temperature can improve flower quality. Generally, with sparse plant density and high temperature, plants will bloom earlier; conversely, flowering will be delayed. When fertilizing during the growing period, note that more nitrogen fertilizer should be applied in the early stage and more phosphorus and potassium fertilizer in the later stage, which can make the plant thick and strong, with many buds, improving flower quality.

If you want the flowers to bloom as scheduled, you can also adjust the flowering period as appropriate according to the characteristics of different varieties. Below we introduce several methods.

Method 1: Sow in batches. By choosing suitable varieties and adjusting the sowing time, you can make them bloom at a specified time. For example, if you want the plants to bloom on National Day, you can plant gladiolus in July. If you want the plants to bloom at New Year's Day or during the Spring Festival, you should choose cold-tolerant varieties and plant them in September, keep the room temperature above 15°C, and care for them carefully, and they will bloom in deep winter. If new corms are planted in December and the room temperature is kept above 15°C, they can bloom around Qingming or May Day the following year.

Method 2: Regulate the flowering period by adjusting corm dormancy. Break plant dormancy to force flowering. Gladiolus has a dormant period. During dormancy, the corms remain unmoved even in an environment suitable for growth. To break its dormancy and make it enter the growing state as soon as possible, cold storage treatment can be used: place it in an environment of 0°C-4°C, refrigerate for 30-50 days, then take it out. Soaking can also be used: place the corms in warm water at 30°C and soak for half a month. Both methods can break dormancy. After planting, they will sprout quickly and enter the growing period.
Low-temperature treatment to delay plant flowering. If the corms are kept in a relatively low-temperature and dry place, the corms will remain dormant and will not sprout. When needed, raise the temperature to end dormancy and promote sprouting. This can delay flowering and make them bloom at a designated time.

Method 3: Use chemicals to force flowering. After planting the corms, water them with an 800 mg/kg chlormequat aqueous solution. Four weeks after planting, pour this chemical onto the corms again. When the plant shows buds and there are about 25 days until flowering, pour it onto the corms once more. This can advance the flowering period by 5-8 days, and the flowers will be larger, more numerous and more colorful.

Method 3: Cut flowers to extend the flowering time. To make the flowering time longer, cut flowers at the appropriate time. It is best to cut the flower spikes in the early morning, when the lowest flower at the base of the flower branch has not yet opened.

Then place it in a vase filled with clean water close to room temperature. Add 0.1% salt and sugar to the water in the vase to extend the viewing time. You can also add a small amount of aspirin to the water, generally 1 tablet per 500 mL of water, which can extend the flower opening time.

Method 4: Gladiolus is a long-day plant, so the method of shortening or extending the light duration can be used to delay or advance plant flowering.

Repotting: Gladiolus is generally planted in the first year, and after flowering in the second year the seed corms are taken out for storage and planted again the following year, so it does not need repotting.

Gladiolus propagation:

Gladiolus propagation is mainly through corm division, and can also be done by cutting corms and sowing seeds.

Corm division propagation: During the process of leafing out and flowering in the current year, the corms of gladiolus gradually form new corms. After the new corms form, the mother plant gradually shrinks and dies. Cormlets also grow at the base of the new corms. The new corms and cormlets can be removed and planted separately. Generally, new corms can bloom in the second year after planting, while cormlets need another year of cultivation before they can bloom.

The operation method is: when the plant begins to wither after flowering and enters dormancy, dig the corms out of the ground, then separate the mother corm, new corms and cormlets one by one. They can be planted immediately, or the cormlets and new corms can be put into bags and dried in the shade in a ventilated place for later use.

Cutting corm propagation: If the number of corms formed in the current year is small and you want to propagate more, cutting corm propagation can be used.

method.

Generally, biennial corms have 4-6 bud eyes. When cutting the corms with a knife, each part should have one bud eye and a rooting part, so that the cut part can survive and grow into a new plant.

Seed propagation: Seed propagation is mostly used when breeding new varieties. Sow as soon as collected. Before sowing, it is best to soak the seeds in warm water for 5-6 hours, which makes the seeds easier to germinate.

If the seeds are sown in the same year, small corms can grow. Dig them out after autumn, dry them in the shade and store them. After planting again the next year, they can bloom. After flowering, keep those with good variety traits and remove those with poor traits.

Overwintering: The corms should be dug out after the first frost, cleaned of soil, air-dried for one or two days, and then stored indoors. Gladiolus goes dormant in winter. The dormant period is generally 30-90 days, and the overwintering temperature should not be lower than 5°C.

Gladiolus pest and disease control:

The common pests and diseases of gladiolus mainly include corm rot, leaf blight, thrips, slugs, etc.
Corm rot: On infected corms, yellow-brown, sunken lesions appear on the surface, surrounded by black ulceration. If cold air is strong at this time, the lesions expand rapidly and grow a blue-green mold layer, and finally the corms shrink and become dry and hard. This disease mostly occurs during corm storage.

To prevent this disease, be careful when first digging out the corms to avoid wounding them. Soak the dug corms in cold water, then disinfect with alcohol, then place them in a ventilated, dry storage room for storage, keeping the storage room temperature at 4°C-5°C.

Leaf blight: On infected plants, yellow spots appear at the leaf tips, and finally a dark brown mold layer appears at the lesions. This disease is most likely to break out from July to September each year.

To prevent this disease, handle carefully before planting. Before planting, peel off the dry, withered scales of the corms, then soak the corms in a 0.5% potassium permanganate solution for about 15 minutes for disinfection, and then plant.

If the plant is already infected, in the early stage, spray 1% Bordeaux mixture of equal proportions or 50% zineb powder 1000 times solution, generally once every 8-10 days.

Thrips: This pest hides in leaf axils during the day and damages leaf stems. On cloudy days or at night, it crawls out to damage leaf surfaces, and also crawls onto flowers to feed on them, causing petals to gradually curl.

If this pest is found, spray with 2.5% deltamethrin emulsion 400 times solution to kill it.

Slugs, also known as shell-less snails, mainly feed on the young buds and leaves of plants, and leave silvery-white trails wherever they pass.

If this pest is found, spray with 3% lime water or 100 times ammonia water to kill it.

Best placement: suitable for a sunny windowsill.

Gladiolus habits, cultivation and care profile [image]

Gladiolus habits, cultivation and care profile [image]

[Common question] What kind of plant exactly is gladiolus?

[Expert answer]

Introduction to gladiolus

Gladiolus (scientific name: Gladiolus gandavensis) originated in South Africa. Varieties include Gladiolus tristis, Gladiolus gandavensis, etc. The flower stem rises above the leaves, and the corolla tube is an enlarged funnel shape. Flower colors include red, yellow, purple, white, blue and other single-color or bicolor varieties.

It is widely cultivated around the world. The main producing countries are the United States, the Netherlands, Israel and Japan, etc. Gladiolus is an important fresh cut flower and can be used for flower baskets, bouquets, vase arrangements, etc. It can be used to arrange flower borders and specialized flower beds.

Dwarf varieties can be grown in pots for viewing. It belongs to the bulbous plants of the family Iridaceae. Together with roses, carnations and gerbera daisies, it is known as one of the "four major cut flowers in the world."

It is widely cultivated around the world. The main producing countries are the United States, the Netherlands, Israel and Japan, etc. Gladiolus is an important fresh cut flower and can be used for flower baskets, bouquets, vase arrangements, etc.

It can be used to arrange flower borders and specialized flower beds. Dwarf varieties can be grown in pots for viewing.

Gladiolus habits, cultivation and care profile [image]

Morphological characteristics of gladiolus

Morphological characteristics

Gladiolus is a perennial herb, with a flattened-round corm at the stem base. The plant height is 90-150 cm. The stem is thick, upright, unbranched or seldom branched. The leaves are hard, sword-shaped, with 7-8 leaves arranged in an overlapping, embedded pattern.

The leaves are 40 cm long and 4-5 cm wide, with many prominent parallel veins. The flower stem rises above the leaves. The spike inflorescence bears 12-24 flowers arranged in two rows, facing to one side. The corolla tube is an enlarged funnel shape, slightly curved upward, with a flower diameter of 12-16 cm. Flower colors include red, yellow, white, purple, blue and other shades, or bicolor varieties. The flowering period is summer and autumn. The capsule has 3 chambers, dehiscing along the back, containing 15-70 seeds. The seeds are dark brown, flat and winged.

Biological characteristics

Gladiolus originated in tropical Africa and the Mediterranean region. It likes cool climatic conditions and fears severe heat and severe cold. It requires fertile, loose, moist, well-drained soil.

Specific habits

The plant height is 80-170 cm. The corm is flat-round or ovate, with annular nodes. Leaves are 6-9, sword-shaped. The scorpioid umbel bears 8-24 flowers, and the flowers are large. Gladiolus likes cool conditions, is not cold-tolerant, and fears severe heat. It requires loose, fertile, moist, well-drained soil. The optimum growth temperature is 20-25°C during the day and 10-15°C at night. Gladiolus is a long-day plant, with 16 hours of light per day being most suitable.

The underground part of gladiolus has corms, fibrous roots and contractile roots. The corm is a dormant organ. If one mother corm is planted in spring, one or several new corms over 2 cm can be harvested in autumn. The corm is flat-round or ovate. The outside of the corm is covered with 4-6 layers of brown membrane coating, which protects the corm. The corm has 3-6 bud eyes arranged in a straight line, with the middle one being the main bud and the side ones being lateral buds. Both the main bud and lateral buds can form new plants, and plants formed from lateral buds can also send up spikes and bloom. Around the base plate of the corm are root primordia, which form fibrous roots after sprouting.

When the plant grows 3 leaves, new corms begin to form on the mother corm, and multiple new roots grow from the new corms -- contractile roots.

With the formation of new corms and contractile roots, the mother corm and fibrous roots gradually shrink and dry up. After the new corms have grown, cormlets are borne between the new corms and the contractile roots. Due to differences in corm size and variety, the number of cormlets borne also differs. The Dahongpao variety can bear up to 50-70 cormlets, while the Ziqixiangyun variety has only 4-8.

Most cormlets are ovate or peach-shaped. The flower stem of gladiolus is drawn out from the leaf cluster. The spike inflorescence is 30-75 cm long. Each flower spike bears 8-24 flowers, usually facing to one side and arranged in two rows. The corolla diameter is 8-16 cm. The corolla gradually becomes smaller from bottom to top, and the flowers open gradually from bottom to top. The corolla tube is enlarged funnel-shaped, trumpet-shaped, bell-shaped, etc., slightly curved upward.

The corm is flat-round spherical, 2.5-4.5 cm in diameter, covered outside with a brown or yellow-brown membranous coating.

The leaves are basal or alternate at the base of the flower stem, sword-shaped, 40-60 cm long and 2-4 cm wide, with a sheath-like base, acuminate apex, arranged in 2 rows in an overlapping pattern, gray-green, with several longitudinal veins and 1 obvious, prominent midrib.

The flower stem is upright, 50-80 cm tall, unbranched, with several alternate leaves on the lower part of the flower stem. The terminal spike inflorescence is 25-35 cm long. Each flower has 2 bracts below it, membranous, yellow-green, ovate or broadly lanceolate, 4-5 cm long and 1.8-3 cm wide, with a prominent midrib. There is no pedicel. The flowers are solitary within the bracts, bilaterally symmetrical, in colors such as red, yellow, white or pink, with a diameter of 6-8 cm. The perianth tube is about 2.5 cm long, curved at the base. There are 6 perianth segments arranged in 2 whorls. The perianth segments of both the inner and outer whorls are ovate or elliptical. The upper 3 are slightly larger (2 outer perianth segments, 1 inner perianth segment). The uppermost inner perianth segment is particularly broad and large, curved into a helmet shape. There are 3 stamens, upright, adnate within the helmet-shaped inner perianth segment, about 5.5 cm long. The anthers are linear, red-purple or dark purple. The filaments are white, inserted on the perianth tube. The style is about 6 cm long, with a 3-lobed apex. The stigma is slightly flat, broad and enlarged, with short hairs. The ovary is elliptical, green, 3-chambered, with axile placentation and numerous ovules.

The capsule is elliptical or obovate, dehiscing along the back when mature. The seeds are flat and winged. The flowering period is July-September, and the fruiting period is August-October.

The underground part has corms, flat-round in shape. The plant height is 60-150 cm. The stem is thick, upright, unbranched or seldom branched. The leaves are hard, sword-shaped, with 7-8 leaves arranged in an overlapping, embedded pattern. The leaves are 40 cm long and 4-5 cm wide, with many prominent parallel veins.

The flower stem rises above the leaves. The terminal scorpioid cyme bears 12-24 flowers arranged in two rows, facing to one side, with a few bearing flowers on all sides. Each flower grows within a herbaceous spathe, without a pedicel. The flowers are large and bilaterally symmetrical. The corolla tube is an enlarged funnel shape, slightly curved upward, with a flower diameter of 12-16 cm. Flower colors include red, yellow, white, purple, blue and other shades in single colors or bicolor varieties, or with spots, stripes, or wavy or wrinkled forms. The flowering period is summer and autumn. The capsule has 3 chambers and dehisces along the back, containing 15-70 seeds. The seeds are dark brown, flat and winged. The basic chromosome number is x=15.

Ecological habits of gladiolus

Gladiolus is a light-loving long-day plant that cannot tolerate cold or freezing. In summer it prefers a cool climate and cannot withstand excessive heat. Its corms begin to sprout at 4-5°C; growth is best at 20-25°C.

It prefers fertile, deep sandy soil and requires good drainage; it should not be planted in heavy clay soil where waterlogging easily occurs. Summer growth in Northeast and North China is better than in Guangzhou and Shanghai. In Shanghai it can overwinter safely outdoors in winter, while in the north the corms must be dug up and stored indoors for the winter.

Gladiolus is native to tropical Africa and the Mediterranean region. Gladiolus is a light-loving long-day plant that cannot tolerate cold or freezing. In summer it prefers a cool climate and cannot withstand excessive heat. Its corms begin to sprout at 4-5°C; growth is best at 20-25°C. It prefers fertile, deep sandy soil and requires good drainage; it should not be planted in heavy clay soil where waterlogging easily occurs.

Summer growth in Northeast and North China is better than in Guangzhou and Shanghai. In Shanghai it can overwinter safely outdoors in winter, while in the north the corms must be dug up and stored indoors for the winter. It is a sun-loving growth type that likes good ventilation and dislikes muggy, hot, wet and cold conditions.

Gladiolus habits, cultivation and care overview [image]

Cultivation Techniques for Gladiolus

Cultivation Management

(1) In production, planting corms is the main method. In spring, grade the corms by size and soak them for 30 minutes in a 800-fold dilution of 70% thiophanate-methyl powder, or a mixture of a 1000-fold dilution of carbendazim and a 1500-fold dilution of captan. Then sprout them at 20-25°C, and they can be planted after about 1 week. For varieties with severe virus infection and obvious degeneration, shoot-tip virus elimination can be used to rejuvenate the plants.

(2) Conventional cultivation of gladiolus refers to cultivation under natural conditions, generally selecting seed corms with a diameter of more than 2.5 cm. Planting methods include ridge planting and bed planting, with a planting depth of 5-10 cm. When gladiolus produces its second leaf, this is exactly the time of flower bud differentiation, and it is especially sensitive to environmental factors. If it encounters low temperature and weak light, the number of “blind flowers” increases.

Generally, when preparing the soil, apply 6-9 kg of nitrogen, 6-12 kg of phosphorus and 7-12 kg of potassium per mu. During the entire growing season, topdressing is needed 3 times: when 2-3 leaves have emerged, when the inflorescence emerges from the leaves, and 15 days after flowering.

(3) For forcing cultivation of gladiolus, the dormancy of the seed corms must first be broken. After the corms are harvested, under natural conditions, dormancy can only be broken after the low-temperature influence from late autumn to early winter. For forcing cultivation, dormancy must be broken artificially: after the corms are harvested, first treat them at a high temperature of 35°C for 15-20 days, then treat them at a low temperature of 2-3°C for 20 days, and then plant them, after which they will sprout and grow normally.

If flowers are required from January to February, plant in October to November; if planted in December, they will bloom from March to May. That is, from planting to flowering takes 100-120 days. For forcing cultivation, the spacing is 15 cm × 15 cm or 25 cm × 7 cm, and 40-60 corms are planted per sq m. After planting, the daytime temperature should be kept at 20-25°C and the nighttime temperature at about 15°C.

(4) Gladiolus can also be cultivated with delayed planting. After the corms are harvested, store them in a dry cold store at 3-5°C, and plant them again in a greenhouse in July to August of the following year. The management work is the same as for forcing cultivation.

(5) Cut flowers can be harvested 60-100 days after planting, with the specific time depending on the variety. The suitable harvest time is when the lower 1-5 florets of the inflorescence show color. Generally, cut them together with 2-3 leaves, and be careful not to damage the leaves left on the lower stem, so that they can continue to supply nutrients to the new corms and cormels. The cut flower stems should be graded and packaged, placed in a storage facility at about 4°C, and delivered to consumers within 3-7 days. If storage or transport time is too long, quality will decline.

Key Cultivation Points

1. Soil preparation and fertilization. For planting gladiolus, sandy loam should be chosen, with deep, loose soil and good drainage, and water accumulation must be avoided. Make raised beds 20 cm high and 1 m-1.5 m wide. Fertilization should include nitrogen, phosphorus and potassium. Since gladiolus is a shallow-rooted plant, fertilizer should be applied shallowly. Topdressing should be done respectively at the two-true-leaf stage (after flower bud differentiation) and at the heading stage, applying diluted manure water plus urea once, applying potassium fertilizer heavily once at the middle stage, and paying attention to controlling nitrogen at the later stage to avoid excessive vegetative growth and lodging. For plots mainly producing corms, potassium fertilizer should be the main additional application.

2. Corm selection and treatment. After determining the cultivar to be cultivated, pay attention to selecting corms. When selecting, make sure the varieties are not mixed and choose seed corms that are free of pests and diseases and have undamaged bud points. Before planting, first soak the graded corms in water for 15 minutes, then soak them for half an hour in 0.1% mercuric chloride or a 80-fold dilution of formalin for disinfection. After taking them out, rinse them clean before planting.

3. Planting time. Under natural conditions, planting is generally done in April to May, when the soil temperature is about 10C. If year-round production is desired, it should be determined according to different flower supply periods. Under conditions where temperature and light are guaranteed, those required to be marketed before New Year's Day should be planted in early September; those marketed during the Spring Festival can be planted in late September; those supplying cut flowers in early spring can be planted from late November to late December. For those flowering from late May to early June, sprouting can be started in early February and field planting done in early April; for those flowering on National Day, planting can be done from early June to mid-July.

4. Breaking dormancy. Corms remain dormant continuously for about 3 months under low-temperature conditions. If earlier planting is needed, first treat them at a high temperature of 35°C for 15-20 days, then treat them at a low temperature of 2C-3C for 20 days to break dormancy. However, during this period the corms should be kept dry, as excessive humidity easily causes corm rot.

5. Planting specifications vary with the plant type of the variety: 20 cm square for large plant types and 10-15 cm square for small and medium plant types. The planting depth is generally 3 cm-10 cm. To prevent lodging, when planting the corms, place 2 layers of 20 cm square nylon netting on the planting bed in advance. Later, as the plants grow taller, tighten the support layer by layer to prevent the plants from lodging and the flower stems from bending.

6. Flower harvesting and corm storage. For harvesting gladiolus flowers, the suitable time is when the lowest flower just begins to open. When cutting flowers, leave 3 green leaves at the base of the plant so that the corms can continue to enlarge. Usually cut flowers in the afternoon, classify them by variety, pack them in bundles of 10 into boxes and send them to market. It is best to dig up the corms when about 1/3 of the leaf tips have withered and yellowed. After digging, cut off the leaves, dry the corms in the sun for several hours, and after the outer skin dries, move them indoors. Grade the new corms and cormels into shallow boxes and store them under dry, ventilated conditions at 5C-11C. During this period, inspect and turn them to prevent heating and mildew.

Cultivation Tips

Gladiolus is a perennial herbaceous flower and one of the world's four major cut flowers. Its flower shape is beautiful, its colors are vivid, and its petals are like thin silk, making it very charming. In nature, some bloom in spring and some in summer.

When the aboveground part turns yellow, the corms can be dug up; for late plantings, they can be dug up in late November. If the leaves are still green when digging the corms, they can be tied in bundles or spread out to dry, then the leaves can be pulled off and the corms taken for storage. The seed corms should be spread thinly on multi-layer racks indoors, requiring ventilation and dryness, and preventing freezing damage. If they have not yet been planted by early summer, some corms begin to sprout, but this does not seriously affect growth and flowering after planting. If they are stored refrigerated at 4-5°C starting in May, there will be no sprouting. It is a light-loving long-day plant; when cultivated in winter, light must be increased on cloudy days, and it is afraid of freezing. The suitable growing temperature is 20—25°C during the day and 10—15°C at night. Corms that have passed dormancy sprout at 4—5°C, and plants freeze to death at a low temperature of 0°C during winter cultivation. It is not tolerant of waterlogging, and the cultivation site must not accumulate water. It prefers fertile, loose, well-drained sandy loam, with a pH of 5.6—6.5 being best.

To promote earlier or delayed flowering, extend the marketing period, and increase the economic benefits of gladiolus cut flowers, through the practice of horticultural technicians and some flower growers in Shuyang County, Jiangsu Province, five methods for regulating its flowering period have been explored and summarized, briefly described as follows:

Regulation by cultivation management measures

In winter, when using small arched sheds for cultivation, appropriately increasing light is beneficial for flowering and improving flower quality; in summer, using shade netting to block light can lower temperature and improve flower quality; using 2-year-3-year crop rotation can prevent pest and disease damage and allow normal growth; large-flowered varieties with sparse density can flower earlier in the high-temperature season, and otherwise flowering is delayed. Fertilization during the growing period should be mainly nitrogen fertilizer in the early stage; in the later stage, when the stem elongates and buds form, phosphorus and potassium fertilizers should be the main ones to promote thick and strong flower stalks and improve flower quality.

Using differences among varieties to control the flowering period

The growth cycle differs greatly among varieties: early-maturing varieties 50 days-60 days, mid-maturing varieties 65 days-80 days, and late-maturing varieties 80 days-120 days. To accurately arrange the marketing time of cut flowers, the countdown method is generally used, that is, calculating the planting time backward from the cut flower marketing time. At the same time, the sowing time of different varieties should be arranged according to the growth cycle of each variety. In addition, regulation of light and temperature can also partially adjust its flowering period. For long-day flowers, more than 14 hours of light are needed per day. Based on this characteristic, shading can be used to shorten the daily light exposure of gladiolus to within 10 hours-12 hours, so as to delay flowering. This measure should only affect flowering within a range of one week; forcibly advancing or delaying the natural flowering period is unfavorable to cut flower quality.

Breaking dormancy to flower earlier

Gladiolus has dormancy, generally lasting 30 days-90 days. During dormancy, even if the environment is suitable, the corms cannot grow. The method of breaking dormancy is mostly low-temperature treatment: place them at 0°C-4°C and refrigerate for 30 days-50 days, which can break sprouting and flowering. The corms can also be soaked in 30°C warm water for two weeks to release dormancy; or the corms can be suspended in a greenhouse for 30 days, then soaked in 27°C-32°C warm water for about 12 hours, and then planted.

Using plant growth regulators to promote earlier flowering

Pouring an 800 mg/kg aqueous solution of chlormequat on gladiolus corms 3 times can increase the number of flowers. The first pouring is after planting the seed corms, the second is 4 weeks after planting, and the last pouring is 25 days before flowering. This can advance flowering by 5 days-8 days.

Extending the corm dormancy period to delay the flowering period

If the corms are kept under low-temperature and dry environmental conditions, the corms can continuously maintain a dormant state and will not sprout or grow, thereby delaying the flowering period. When flowering is needed, raise the temperature in advance and provide suitable sprouting conditions so that the corms end dormancy and flower as scheduled.

How to Grow Gladiolus

Field Management

For cultivating gladiolus, choose a sunny, well-drained sandy loam rich in humus; although it can grow and flower in clay soil, the development of renewal corms is poor, and few cormels form under the large corms. Before planting, sufficient base fertilizer should be applied to the soil, and a base fertilizer rich in phosphorus and potassium is best. The planting depth varies with soil properties and corm size, generally 5-10 cm, with a spacing of 15-25 cm. During the growing period, apply topdressing 3 times. The first is after two leaves unfold, to promote sprout, stem and leaf growth; the second is when 4 leaves have formed, the stem is elongating and buds are forming, to promote thick and strong flower branches and large flowers; the third is after flowering, to promote the development of renewal corms. Sunlight during the growing period is beneficial to flower bud differentiation and development. In summer, if drought occurs, irrigation should be sufficient, and at the same time pay attention to drainage and irrigation during the rainy season.

Propagation Methods for Gladiolus

Gladiolus propagation is mainly by corm division. New corms flower the following year. To speed up propagation, the corms can also be cut into pieces, each piece must have buds and root-producing parts, the cuts should be coated with plant ash, and after slight drying they can be planted. When breeding new varieties, seed propagation is mostly used. Seeds collected in autumn are sown immediately and have a high germination rate; in winter the seedlings are moved into a greenhouse for cultivation, and in the following spring they are transplanted separately outdoors. With strengthened management, some seedlings can flower in autumn.

1. Seed propagation

Seed propagation is mainly used for crossbreeding and the selection and breeding of new varieties, and is rarely used in production. Gladiolus seeds have no dormancy period, and the seed lifespan is relatively short, so they should be sown immediately after harvest, generally in early to mid-September, using the broadcast sowing method. The suitable germination temperature is 20°C, seedlings can emerge in 25-30 days, and they can flower in 2-3 years.

2. Division propagation

This method is mostly used in production. After the aboveground part of gladiolus dies, dig out the corms, remove the small cormels attached to the large corms, grade them, dry them fully, and store them in a ventilated and dry place at 5-10°C. The following year they can be planted in rows, and after 1-2 years of cultivation they can flower. In addition, propagation can also be done by cutting the corms. Select robust large corms, remove the outer skin, and use a sterilized sharp knife to cut the corms into several pieces. Each piece must carry more than one stem bud and part of the basal plate. After cutting, coat the basal plate with plant ash, charcoal powder or sulfur powder to prevent rot. After drying, plant them with the stem buds facing upward in cultivation soil at a depth of 5-10 cm. Generally they can flower in the same year. This method is now rarely used.

3. Tissue culture

Dormant buds, axillary buds and corm pieces can be used as explants for tissue culture.

Editor's summary:Gladiolus is also called sword lily. It is planted in many places and can be used as an ornamental plant. It has very good uses in gardens and flower borders.