How to grow balloon flower (Platycodon grandiflorus)? A complete guide to its care and management

Few gardening enthusiasts grow balloon flower at home themselves. Because of its relatively high medicinal value, many flower farmers cultivate it on a large scale for medicinal use, and balloon flower is also edible. However, balloon flower is a strongly cyclical plant, so its price fluctuates considerably.

Balloon flower

I. Site selection

Balloon flower grows best in relatively loose soil, and is especially fond of sloping land and mountainous land, with a semi-shaded, semi-sunny position being best; when grown on flat ground it needs good drainage conditions. Balloon flower is not suitable for continuous cropping.

II. Soil preparation

Balloon flower has fairly long fleshy roots, so it is best grown on ridges. In early spring (mid to late April), spread farmyard manure and plow the soil deeply, harrow it fine and level it (deep plowing of 30 cm). When making the ridges, first mark grid lines on the ground at 2 m intervals, open furrows, then move the soil from the furrows to both sides, making ridge beds about 1.7 m wide with furrows about 30 cm wide; if drought occurs, irrigate along the furrows in preparation for sowing.

III. Fertilization

Before sowing balloon flower in the field, apply 2000-3000 kg of farmyard manure per mu, 40 kg of grain compound fertilizer and 30 kg of superphosphate. To control white grubs, when turning the farmyard manure, mix in 1 kg of Jiadifen powder per ton of manure evenly and apply it before plowing. For later topdressing, mainly use clear manure water or urea; in July of the same year and in July-August of the following year, use 25 kg of urea or clear manure water for topdressing to promote seedling growth. Clear manure water can be applied at about 2 tons per mu each time, at a concentration of about 10%. If the concentration is relatively high after topdressing, promptly wash the seedlings with clean water.

Key points for autumn care of courtyard flowers

Key points for autumn care of courtyard flowers

(1) Characteristics of the autumn climate. According to traditional Chinese custom, around August 8 on the Gregorian calendar is the day of "Liqiu" (Start of Autumn) in the Chinese lunar calendar, meaning that from this day until "Lidong" (Start of Winter) in early November is "autumn."

In East China, the average daily temperature in autumn is generally between 10 and 22 degrees Celsius, a temperature favorable for plant growth. But autumn is also a transitional season from summer to winter, and temperatures vary greatly. In early autumn the highest temperature is still above 30°C, and can even reach 35 degrees Celsius, while in late autumn the lowest temperature is below 0 degrees Celsius.

In this season, the warm, moist southeasterly wind from the Pacific Ocean is gradually replaced by the cold, dry northwesterly wind from the northwestern highlands. When the northwesterly wind forms and breaks out southward, the lower atmosphere is controlled by cold air while the upper layer is controlled by subtropical airflow, creating the clear, crisp autumn weather.

Autumn is also an important turning point in plant growth. Many herbaceous flowers have finished blooming, their seeds have ripened, and their life cycle has ended; they need to be seed-collected and sown to prepare for the next life cycle. The growth of perennial flowers and trees begins to slow or stops, and some trees begin to shed leaves and are about to enter dormancy to get through the cold winter. Another group of winter-flowering plants that are dormant in summer, such as cyclamen, primrose and calla lily, begin to wake up and enter a new period of vigorous growth, so water and fertilizer must be kept up.

(2) Daily management of autumn flowers

① Management methods: In autumn, for flower growers, in addition to continuing the daily summer management of watering and fertilizing, there are many "special" things to do as the climate changes.

Early autumn: At this time the high summer temperatures have not completely receded, and especially the midday heat is still a threat to flowers and trees. Therefore, the summer shade curtains should not be removed hastily; just open the curtains in the morning and evening for light and air, and keep shading during the rest of the time. Some flowers need even more special attention.

For orchids, maintain a moist and cool environment; it is best to mist 2-3 times a day, spraying in a fine mist until the leaf surface is moist. Sprinkle more water on the balcony, ground or sand bed to help lower the temperature and prevent the threat of the "autumn tiger" (late-summer heat).

For lotus grown in vats in summer, although the flowers have completely faded, it is still necessary to ensure sufficient water and light. Once the seed pods mature they can be picked off, letting the lotus rhizomes continue to grow and ensuring abundant blooms next year.

For kumquat, an excellent plant for winter fruit display, when it blooms for the third time, do not let rain fall directly on the flowers, to ensure a good fruit set rate.

The flower buds of rhododendron are differentiating; reduce watering and apply more phosphorus fertilizer to ensure vigorous blooming next spring.

Cyclamen and mature clivia can be repotted with fresh soil to ensure the potting soil is loose and nutrient-rich, and to prevent blind flowers or "stuck arrows" (flower stalks that fail to emerge).

Geranium, the pride of the balcony, after a summer of continuous growth and blooming, also needs repotting with fresh soil and pruning and shaping. For pruning, cut off the flowering branches, leaving only stubs about 10 cm high at the base to encourage new shoots and keep the plant robust and shapely. Within 1 week after pruning, do not water or fertilize, to prevent infection of the cuts.

For chrysanthemums, do the final pinching and apply more topdressing until the flower buds differentiate.

Mid-autumn: At this time sunlight gradually weakens, the summer heat has dissipated, and temperatures drop noticeably. For flowers and trees that were shaded in summer, gradually reduce the shading time or remove the curtains.

As temperatures drop and sunlight weakens, the water and fertilizer consumption of most flowers and trees decreases accordingly. Watering can be changed from twice daily in summer to once every 1-2 days or once every 2-3 days, and fertilizing can be changed from 1-2 times a week to once every 1-2 weeks.

At the same time, special attention should be paid to the following:

First, after camellia buds appear, apply phosphorus fertilizer once to ensure bright blooms the following year.

Second, after calla lily goes dormant and new leaves are emerging, be especially careful when watering not to pour water into the leaf sheaths, to prevent rot.

Third, for kumquat, the "good fruit of the New Year," fertilize frequently, preferably with fermented soybean cake water mixed with bone water or turtle intestines, ensuring ample water and fertilizer so that it bears abundant fruit.

Fourth, early September is the suitable time for artificial hybridization of dahlia, so artificial pollination should be carried out promptly.

Fifth, for stump bonsai such as Sageretia, elm and hackberry, this is an important time for shaping and styling; leaves can be picked and branches wired, and a light fertilizer applied to encourage new leaves; once the leaves are uniform, prune again into flat pads.

Late autumn: Around October 8 comes Cold Dew, and around the 24th comes Frost's Descent; daylight grows shorter, autumn colors fully appear, and the average daily temperature is generally below 10 degrees Celsius. Once a cold wave arrives, nighttime temperatures can drop below 0 degrees Celsius, with frost or freezing. At this time, be sure to pay constant attention to weather forecasts and promptly move flowers and trees indoors and take cold-protection measures.

In late autumn, the timing of moving plants indoors must be well judged, moving flowers and trees kept on balconies or in the open into the house to overwinter, commonly called "moving indoors." Whether this timing is accurate has a great bearing on whether flowers and trees overwinter safely. If moved indoors too early, the indoor temperature is too high; if moved indoors too late, the flowers and trees suffer cold damage and may even freeze to death. Thus for flower growers, "moving indoors" is also a major matter that cannot be handled carelessly. Moving indoors should be carried out in batches according to the different temperature requirements of different kinds of flowers and trees.

Tropical flowers and trees such as milan (Aglaia odorata), lucky bamboo, Brazil wood, cordyline and croton, commonly called high-temperature-type flowers and trees, have the weakest cold resistance; generally once the normal temperature falls below 10 degrees Celsius they are prone to cold damage, ranging from leaf drop, flower drop, fruit drop and shoot tip damage to death in severe cases. Therefore, such flowers and trees are best sent to a greenhouse for fostering before winter arrives. If they cannot be fostered, move them indoors before the temperature drops below 10 degrees Celsius, place them in a warm, sunny spot, open windows for ventilation at noon on sunny days, and when a cold wave comes use insulation measures such as double-potting or plastic bag covers; in the coldest weather, heating measures are needed.

Carnation, clivia, asparagus fern, jasmine and cacti, commonly called medium-temperature-type flowers and trees, are hard-pressed to withstand low temperatures below 5 degrees Celsius. Therefore, when the nighttime minimum temperature reaches 5 degrees Celsius, they should be moved indoors. When the weather is very cold, bag protection is also needed.

Camellia, rhododendron, orchid, sago palm and banana shrub have relatively good cold tolerance and need not be moved indoors in a hurry if there is no frost or rain or snow. But if the low temperature is below 0 degrees Celsius, they should be moved indoors and placed in a south-facing room, where they can generally overwinter safely.

Five-needle pine, Buddhist pine, crabapple and Chinese rose, commonly called low-temperature-type flowers and trees, have relatively good cold tolerance and generally need not be moved indoors; simply place them in a warm, sunny spot outdoors. Once severe frost or rain or snow occurs, temporarily cover them with straw curtains for protection.

Management after flowers and trees are moved indoors is also very important. After moving indoors, water consumption decreases; generally small pots are watered once a week, and larger pots once every 1-2 weeks. If the potting soil is not very dry, the watering interval can be extended further. Apart from winter-flowering plants such as bird of paradise, cyclamen and clivia, which need sufficient water and fertilizer plus extra phosphorus fertilizer, autumn-sown herbaceous flowers that will bloom in early spring the following year also need frequent fertilizer and ample water. For ordinary flowers and trees moved indoors to escape the cold, apply fertilizer only once every 1-2 months or simply stop fertilizing, to avoid excessive fertilizer causing leggy growth and reducing cold resistance.

October is the best season for transplanting or dividing spring orchids (Cymbidium); orchid growers must not miss this timing. At this time the orchids' growth is relatively weaker, and if the flower buds are not damaged during the operation, next year's blooming will not be affected. To make division easier, watering can be controlled for several days before dividing, letting the potting soil dry appropriately so the roots turn white and become softer, so that roots are less likely to break during transplanting or division. But do not let it get too dry; excessive dryness is also bad for orchid growth.

② Autumn harvest and autumn sowing: Autumn is also the season for propagating seedlings. As the saying goes, spring flowers are sown in autumn; large numbers of spring flowers such as cineraria, cyclamen, pansy and corn poppy need to be sown at this time, and seedling-stage management must be done well.

As the saying goes, good seed makes good seedlings, so sowing must begin with seed collection. How can the best seeds be obtained? Generally speaking, during the peak flowering period of flowers and trees, when the climate is suitable and nutrients are abundant, the seeds produced are naturally of better quality, so grasping the accurate seed-collection time is the first rule. Of course, even within the same batch of seeds there will be individual differences. For home flower growing, the amount of seed used is not large, so the method of selecting seed by seed can be used, keeping those seeds that are well developed, regular in shape and plump and full.

According to the ripening times of different seeds, we can collect the following seeds in each period.

Seed collection: In early autumn, seeds that can be collected include tree peony, large-flowered purslane, zinnia, iris, redbud, bridal wreath spirea, cypress vine, lily, mimosa, centella, water lily, coreopsis and lotus. In mid-autumn, seeds that can be collected include cypress vine, morning glory, balloon flower, zinnia, spider flower, iris, petunia, Chinese peony, mallow, amaranthus tricolor, okra, Emilia sonchifolia, strawflower, periwinkle, cockscomb, mimosa, canna, Lilium concolor and Lychnis fulgens. In late autumn, seeds that can be collected include morning glory, cosmos, okra, hosta, marigold, salvia, four-o'clock, magnolia, trailing lantana, wisteria, Weigela florida, camellia, crape myrtle, Cucurbita pepo, ornamental pepper, China aster, lycoris, red-hot poker, Japanese anemone, Sinojackia xylocarpa, Cornus officinalis and goji.

Different seeds vary greatly in lifespan. Some need a period of storage and full dormancy before they will germinate, such as Sinojackia xylocarpa. Some need to be sown as soon as they are collected, otherwise their germination rate will decrease, such as the seeds of tree peony and Chinese peony, which must be sown immediately after collection or stored in sand. For example, water lily seeds must be stored in water. Generally, seeds of flowers and trees are dried after collection, then placed separately in small paper bags or cloth bags and kept on top of a cabinet or in a drawer; when it is time to sow, take them out and use them.   

Sowing: In early autumn, flowers and trees suitable for sowing include tree peony, primrose, cineraria, hollyhock, dianthus, pot marigold, pansy, daisy, snapdragon, campanula, stock and wallflower. In mid-autumn, flowers and trees suitable for sowing include hosta, balloon flower, China aster, cornflower, pot marigold, hollyhock, mallow, stock, petunia, snapdragon, primrose, nasturtium, verbena, pansy, cineraria and cyclamen.   

In late autumn, sowing of biennial herbaceous flowers should already be finished; a few perennial woody or bulbous flowers and trees, such as cyclamen and heavenly bamboo, can be sown in pots.   

Autumn sowing can be divided into two methods: open-ground sowing and indoor sowing. For cold-hardy herbaceous flowers such as daisy, corn poppy, pot marigold and pansy, open-ground sowing is generally suitable, with the same method as spring sowing. For less cold-hardy flowers such as primrose, cyclamen and clivia, indoor sowing is used. Indoor sowing containers can be a sowing box or a sowing pan. A typical dedicated sowing box is nailed together from wooden strips, about 10 cm high and 40-60 cm long and wide. A suitably sized packaging box at home can also be used instead. A sowing pan is a clay pan with a rim diameter of 30 cm, a height of 10 cm and many round holes in the bottom (available at flower markets). The specific sowing steps are as follows:

Step 1: First cover the round holes in the bottom of the pan with broken tile pieces, and lay a layer of broken tile granules (broken clay pots smashed into bean-sized pieces) or coal cinders and charcoal crumbs, 3-4 cm thick, at the bottom to aid drainage.   

Step 2: Fill the upper part with sterilized potting soil (usually mixed from 3 parts humus soil, 1 part garden soil and 1 part sand) up to 1 cm from the rim of the pan, and pat it level gently with a pressing board.

Step 3: Sow the seeds evenly. The sowing method can depend on seed size: for tiny seeds such as those of primrose, mix in some potting soil, mix evenly and scatter uniformly; for larger seeds such as clivia and cyclamen, place them one by one at 1-2 cm spacing, pressing lightly as you place them so that half of each seed enters the soil and half is exposed, then sift a layer of quartz sand over them with a fine sieve (a discarded window screen can be used at home) to cover the seeds.

Step 4: Take an ordinary plastic basin, fill it half full of water, and place the sowing pan in the water, letting water seep slowly into the pan from the bottom holes until the surface is entirely moist, then take it out and place it in a shaded, ventilated spot on the balcony. Cover with glass to keep warm and moist. Note: turn the glass cover over every day so that the water condensed on its surface evaporates, and leave a small gap for the potting soil to breathe. If the potting soil dries out, spray a little water. After the seedlings emerge, gradually remove the glass cover, then gradually move them to a sunny spot (note: gradually, not all at once into harsh sun, otherwise they will be scorched). According to how dry or moist the potting soil is, water in time with a fine watering can. After the seedlings produce true leaves, use a thin bamboo stick to gently remove the overcrowded and poorly growing seedlings, keeping the robust, uniform good seedlings. When the seedlings have produced 3-4 true leaves, they should be transplanted into pots.

Methods for sterilizing potting soil include a dedicated drying oven. At home, you can buy sterilized bagged potting soil; you can also spread the soil flat on a concrete rooftop on a sunny day and sun it for 1-2 days; or put it in an iron wok and stir-fry over high heat for half an hour; you can also spray the soil with 0.5% potassium permanganate water, cover it tightly with plastic film and let it sit for half a day, remove the film, and use it after 1 week. When sowing, to prevent dust from flying, you can first spray a small amount of water into the potting soil to moisten it slightly, but never use much water, otherwise the soil becomes sticky and hard to work with.

Most herbaceous flower seeds can be sown directly without any treatment before sowing. However, some seeds have thick, hard or waxy seed coats, such as cyclamen, and are best pre-treated before sowing to promote germination and sterilize them. The treatment method is soaking in water; for seeds with thicker seed coats, warm water can be used (water temperature around 60 degrees Celsius), and the soaking time is generally 24 hours; after sowing, spray more water to keep them moist. In addition, for seeds with hard seed coats such as lotus, one end of the seed coat can be filed open with a rasp, then soaked. For seeds purchased from other places, to prevent diseases infecting the seeds from spreading locally, soak them in 0.5% potassium permanganate or 0.3% copper sulfate solution for 5 minutes, then take them out, rinse clean with water and sow.

Some herbaceous flowers, such as primrose, pocketbook flower and cineraria, need transplanting after sowing. Others are not suitable for transplanting, such as corn poppy and California poppy; these flowers and trees have overly delicate roots and grow poorly after transplanting, so when the seedlings first put out true leaves they must be potted into small pots 13 cm in diameter, and after they grow a little larger, removed from the pots and planted out, or the direct-sowing method can be used.

(3) Autumn pest and disease control for flowers. Autumn's high temperatures and dryness make it a peak season for flower spot disease and powdery mildew.

Spot disease is caused by fungi and includes black spot, brown spot and red spot, often occurring on leaves and fruits. In the early stage of the disease, round spots of varying sizes appear on leaves or fruits, fading from green to yellow, with a clear outline at the outer edge. Mold layers or small black grains often appear on the spots, and in the later stage the diseased part necroses.

Powdery mildew is also caused by powdery mildew fungi and mostly occurs on leaves, young fruits and tender shoots. The lesions are nearly round, with a thin layer of white powder on them; in the later stage many yellow-brown grains the size of pinheads are scattered on the white powder layer. Removing the white powder layer reveals yellow spots on the affected plant tissue. Chinese rose, dahlia and others are prone to this disease.

The fundamental method of preventing and controlling the above diseases is to pay attention to hygiene, thoroughly eliminate the source of disease, and promptly clean up dead branches and fallen leaves inside and outside flower pots and on balconies and in courtyards. If many flowers are grown, spray with 50% carbendazim wettable powder at 500-1000 times dilution for disinfection. Those growing Chinese peony, tree peony, chrysanthemum and carnation can also spray once every 10 days with 120-160 times Bordeaux mixture of equal amounts, which can prevent tree peony red spot disease, carnation leaf spot disease and chrysanthemum brown spot disease.

In addition, applying more phosphorus and potassium fertilizer to flowers and trees to enhance disease resistance is also an effective method. At the same time, pests such as aphids, red spider mites and whiteflies are also likely to occur at this time, so check plant by plant. Once found, immediately catch them carefully by hand. When there are many, spray dimethoate and omethoate to kill them.

Before moving flowers and trees indoors in late autumn, check pot by pot and branch by branch. If there are scale insect eggs on the branches, immediately scrape them off clean with a bamboo slip. Aphids are relatively large and easy to spot, but red spider mites are extremely small and mostly on the undersides of leaves, hard to notice. Therefore, check the undersides of leaves plant by plant. If small white dots are found, immediately spray with a dimethoate preparation to kill them, or wash with tobacco infusion (about 20 cigarette butts soaked in a bowl of water for 24 hours, then mixed with some soapy water or laundry detergent), and rinse clean with water after washing.

If fertilizer, water and everything else are normal but the plant seems to grow poorly, you should suspect whether there are pests harming it in the soil. The simplest and most effective way is to check by repotting, seeing whether there are cutworms, ants, earthworms, etc. in the soil; if there are, remove them promptly. When repotting, mix some carbofuran into the soil (for a flower pot 20 cm in diameter, use about one small plastic spoon), or use 2 tablets of "Baihualing" sold in shops, crushed and mixed into the soil, which also has a good sterilizing and insect-killing effect.

What needs special mention here is that in home flower growing, pests and diseases should be checked frequently, discovered early and controlled promptly, using manual capture or water washing as much as possible. When pesticides must be used, use non-toxic and low-toxicity pesticides as far as possible, and spraying pesticides indoors is absolutely prohibited.

Key points for growing and caring for lobelia, the emerald butterfly flower of courtyard flowers