A Detailed Guide to Grafting Cultivation Methods and Precautions for Michaelmas Daisies

  Michaelmas daisies are prolific in bloom and brilliant in color, with strong adaptability. In particular, the new cultivars introduced in recent years are shorter in stature and naturally well-formed, and their peak blooming season falls right around National Day, so they are mostly used as flowerbed and flower border material, and can also be planted in mass or in clumps, or used as potted flowers or cut flowers.

  Michaelmas daisies are grafted onto wild yellow wormwood as rootstock, with good results. The specific method is as follows:

  At the end of November or the beginning of December, remove the spent flowers from the Michaelmas daisies and repot them with fresh soil. When the outdoor temperature drops to around 5°C, move the pots into a low-temperature greenhouse; they must not be placed in a medium- or high-temperature house, lest they sprout and grow leggy, making the chrysanthemum seedlings too weak to withstand the slightest wind.

  After the Beginning of Spring the following year, move the potted chrysanthemums to a sheltered spot outdoors, and around Qingming apply a moderate amount of diluted liquid fertilizer such as human waste. From the end of April to the end of June, dig up yellow wormwood seedlings from the wild and plant them in clay pots 5 cun or 7 cun in diameter; in June and July, depending on the size of the yellow wormwood plants, transfer them to 8-10 cun clay pots, applying diluted liquid fertilizer once every 5 days.

  When the yellow wormwood stem reaches 15 cm in height, Michaelmas daisies can be grafted onto it using the cleft grafting method. After grafting, cover with a small plastic bag to retain moisture, and the graft will take in about 7 days. Note that the rootstock height should preferably be around 15 cm; if it exceeds 20 cm, the Michaelmas daisy will later feel top-heavy and its stem will be unstable.

  Second, if the inner core of the yellow wormwood rootstock at the graft union has already turned white and aged, it is not suitable for grafting, because the graft will not easily take, and even if it does take, the scion will become stunted and fail to grow.

  After the Michaelmas daisy graft has taken, apply diluted liquid fertilizer frequently, with management the same as for cultivating autumn chrysanthemums. Normally, the Michaelmas daisy can be pinched directionally into shapes such as a sphere or a flattened steamed-bun form, but the final pinching must be done on all heads at the same time. If you want it to bloom for National Day, do the final pinching at Minor Heat (early July); if you want it to bloom during the autumn chrysanthemum exhibition, do the final pinching in late July. Testing has shown that the largest sphere formed by the flowers of a single grafted Michaelmas daisy plant can reach about 35 cm in diameter, which is quite spectacular.

  The Michaelmas daisy has capitula (head-like flower heads) that are densely borne, with a flowering period from August to September; flower colors include blue, purple, red, white and so on. It is commonly propagated by sowing, cuttings and division. For sowing, sow in spring in April; germination occurs 12-14 days after sowing, but superior cultivars tend to degenerate. Cuttings are taken in spring and summer, using tender stems as cuttings. Roots form 18-20 days after cutting. Division can be done in spring or autumn, generally once every 3 years.

  To make the plant full and shapely with abundant, brilliantly colored flowers, the following should be noted during cultivation:

  1. Timely pruning and pinching. The Michaelmas daisy is a plant that tolerates pruning well; pinching and pruning can promote dense flowering.

  2. Fertilizing and watering. Apply sufficient base fertilizer before planting, and during the growing season apply diluted cake fertilizer once every 2 weeks to promote vigorous growth. Water as appropriate, and water promptly in dry weather.

  3. If pests or diseases are found during cultivation, spray with pesticides promptly. Michaelmas daisies are generally susceptible to powdery mildew, so do not plant them too densely, pay attention to controlling humidity and ventilation, and spray promptly once infection is found.