How to Grow Potted Geraniums? A Detailed Guide to the Latest Care Methods
Geranium is also known as zonal geranium, scarlet geranium, mosquito repellent plant, etc. It is a shrub flower plant of the genus Pelargonium in the family Geraniaceae. Young plants are succulent herbs, while old plants are semi-lignified. It has strong adaptability, bright flower colors, and a long flowering period. In the West, it is an excellent flower for decorating windowsills, and it is suitable for indoor display, flowerbed arrangement, etc. Now let us take a look at how to grow potted geraniums!
Geranium Growth Habits
Geranium prefers warm winters and cool summers. In winter, keeping the indoor temperature at 10-15 degrees C every day, with a nighttime temperature above 8 degrees C, is enough for it to bloom normally. However, the optimal temperature is 15-20 degrees C. It likes dryness and dislikes dampness, so it should not be watered too much in winter; water only when the soil is dry, and let it dry between waterings. If the soil is wet, the stems become soft and tender, which is unfavorable for the sprouting and opening of flower branches. Long-term excessive moisture will cause the plant to grow leggy, the flower branch attachment point to move upward, and the leaves to gradually turn yellow and fall off. During the growing period, it needs sufficient sunlight, so in winter it must be placed in a sunny spot. With insufficient light, the stems and leaves grow leggy, the flower stalks become thin and soft, and the inflorescence develops poorly. Under weak light, flower buds often fail to open smoothly and wither early. It does not like heavy fertilizer; too much fertilizer will make geraniums grow too vigorously, which is unfavorable for flowering.
Geranium Cultivars
1. Trailing geranium: Trailing geranium is also known as ivy-leaved geranium, climbing geranium, etc. Its varieties include the purple-red Amethyst, the pink Lambada 98, the semi-double deep red Shone, the semi-double pink Penvey, and the single white Tornado. There are also tetraploids such as the pink Freckles and the large-flowered bright red Tetra Red.
2. Scented geranium: Scented geranium is also known as fragrant geranium, and its trade name is mosquito repellent plant. It is widely popular because the plant has volatile fragrance and can be used to make essential oil. Its main components include geraniol, citronellol, linalool, etc. There are many types of fragrance, including lemon scent, rose scent, fruit scent, etc. Because cultivation and management are easy and essential oil yield is high, it can be used as a substitute for other essential oils with low yields, such as rose essential oil or neroli essential oil.
3. Horseshoe geranium: Horseshoe geranium is a subshrub plant, with a plant height of 30-80 cm. The stems are upright, cylindrical, and nearly succulent. The leaves are ovate-peltate or obovate, with dark brown horseshoe-shaped rings on the leaf surface, and the leaf margins have blunt serrations. The flowers range from deep red to white, there are relatively few flowers, and the flowering period lasts all year.
4. Regal geranium: Regal geranium is 30-40 cm tall, with upright, branching stems. The base is lignified and covered with spreading long soft hairs. The leaves are alternate, the stipules are dry and membranous, triangular-ovate, and the leaf blades are round-reniform, with a cordate or truncate base. The umbel is opposite the leaves or axillary, clearly longer than the leaves, with several flowers. The sepals are lanceolate, and the corolla is pink, pale red, deep red, or white.
Geranium Propagation Methods
1. Sowing: Geranium sowing propagation can be carried out in spring and autumn, and indoor pot sowing in spring is preferable. The suitable germination temperature is 20-25 degrees C. Geranium seeds are not large, so after sowing, the covering soil should not be deep, and they germinate in about 2-5 days. If sown in autumn, they can bloom in the summer of the following year. Seedlings propagated by sowing can be used to select excellent intermediate-type varieties.
2. Cuttage: Geranium cuttage is best in spring and autumn. Choose cuttings 10 cm long, with the top part being the best, as it has strong growth vigor and roots quickly. After cutting the cuttings, let the cut surface dry for several days to form a thin film, then insert them into a sand bed or a mixed substrate of expanded perlite and peat. Be careful not to damage the stem skin of the cuttings, otherwise the wound is prone to rot. After insertion, place them in a semi-shaded place and keep the room temperature at 13-18 degrees C. After that, they root in 14-21 days.
3. Tissue culture: Geranium can also be propagated by tissue culture. Using MS medium as the basic medium, add 0.001% indoleacetic acid and kinetin to promote explants to produce callus and adventitious buds, and use 0.01% indoleacetic acid to promote rooting. The tissue culture method provides a new way for the good-seed breeding and iterative breeding of new varieties of geranium.
How to Grow Potted Geraniums?
1. Soil: Geranium also has strong adaptability and can grow in various soil types, but it grows best in sandy loam rich in humus. Mixing some sandy soil into the soil bought at the flower market will have a better effect. Geranium grows relatively quickly and needs to be repotted once a year, in early spring. When repotting, remove old roots and old soil, and move it outdoors to a sunny place in late April for care.
2. Temperature: Geranium likes a warm, humid, and sunny environment. The most suitable temperature for growth is between 10 and 20 degrees, which is the temperature of spring and autumn. Therefore, protective measures must be taken for it in both winter and summer. If it is winter, it should be placed in an environment with a temperature not lower than 0 degrees C to avoid frostbite, while in the hot summer, it should be moved to a cool place to avoid exposure to the scorching sun.
3. Water: Geranium is a plant that does not like too much water. Therefore, during cultivation, never water geraniums too much. If watered too much, the roots of the geranium will rot. If it grows in such a watery environment for a long time, it will affect its growth and cause death. Therefore, when growing geraniums, it is enough to water it once every two to three days, but each watering must be sufficient.
4. Fertilization: Applying too much fertilizer to geraniums at one time will cause dehydration. If too much fertilizer is applied, watering more frequently afterward can alleviate the symptoms. However, if it is not fertilized for a long time, it will also cause insufficient nutrients. The amount of fertilizer applied to geraniums is directly related to its soil quality, flower size, and pot size.
5. Light: Geranium needs sufficient sunlight during the growing period, so in winter it must be placed in a sunny place. With insufficient light, the stems and leaves grow leggy, the flower stalks become thin and soft, and the inflorescence develops poorly. Under weak light, flower buds often fail to open smoothly and wither early. Sufficient sunlight helps geraniums bloom. In spring and autumn, expose them to more sunlight. In summer, pay attention to the temperature. If the temperature is too high, avoid exposing geraniums to light.
6. Pests and diseases: If geraniums are poorly ventilated and too humid, they are prone to leaf spot and flower wilt. After discovery, attention should be paid to ventilation, and the diseased flowers and leaves should be removed immediately to prevent infection, and an equal amount of Bordeaux mixture should be sprayed for control. The main pests are red spiders and whiteflies, which harm leaves and flower branches, and can be killed by spraying 1000 times liquid of 40% omethoate emulsifiable concentrate.
7. Pruning: Reasonable pruning of geraniums can promote more flowering. Usually, the plant should be pinched back several times to promote more branching and bud formation. After the flowers fade, remove the residual flowers in a timely manner and cut off overly dense and thin weak branches to avoid excessive consumption of nutrients. However, in winter when it is cold, heavy pruning is not suitable.