One of my gardening friends grows blooming plants with single flowers almost exclusively. She maintains that double flowers are not as “natural” looking (and actually the majority of native plants do produce single flowers), and that single flowers are much more enticing to pollinators (and I must concur that the flowers that attract the most bees in my garden are single ones).
On the other hand, I make flower arrangements, so find double flowers very useful for that purpose. Single blooms can also look great in bouquets but some outstanding designs can be created using spectacular double blossoms, and some of the most stunning are produced by a plant grown from tubers — the ranunculus.
Ranunculus flowers have layers of petals that have the texture of poppy petals and are tightly packed together to create beautiful flower heads six to 10 cm in diameter. They are great cut flowers and come in vibrant colours ranging from white to yellow, orange, red, gold, violet and pink. Often called Persian buttercup, it is officially named Ranunculus asiaticus, and is native to the Far East.
Ranunculus tubers resemble fleshy paws with pointed fingers. Some say they look like large dead spiders; others say they look like dried miniature banana bunches. When they are purchased — usually in bags of mixed colours — they look completely dehydrated, but after being soaked for 24 hours they plump up to twice their original size. The bigger the tubers the more blooms they will produce, so choose the largest ones you can. The soaked tubers are planted in the ground or in containers with about three cm of soil covering the tops. The pointed claws should face downward with the fuzzy eye of the tuber on top, as the new growth will emerge from the eye. Tubers should be planted about 10 cm apart in a well-drained soil.
After planting, the soil should be watered thoroughly, making sure it drains well, and then watered daily for the next four or five days to give the tubers a good start. After that, water the soil to keep it evenly moist but not soaking wet or waterlogged. Ranunculus like a sunny exposure although a semi-shaded location will suffice. When the new growth emerges and has developed somewhat, a 20-20-20 soluble fertilizer can be added to the water at half-strength once a week to promote bloom and plant vigour.
In our area ranunculus are treated as annuals; they are classed as Zone 7 and will not survive any exposure to frost. They do, however, prefer cooler temperatures, so will perform best in early summer and early autumn. For this reason, ranunculus are often started indoors to get early bloom before midsummer heat arrives and then more are planted in midsummer to coincide with the arrival of cooler autumn temperatures.
Ranunculus will start to bloom about eight weeks after their initial soaking, so tubers planted indoors in early April will begin to bloom in early June and will produce blooms for about a month before beginning to flag. Tubers soaked and planted in early July will come into bloom in early September, providing vibrant colour to the autumn garden. If grown in containers, the plants can be brought indoors during nights when temperatures dip toward freezing. Because of the cool fall temperatures, ranunculus grown in the autumn tend to be a bit shorter, have thicker stems, more branches and therefore more blooms per plant.
Flower arrangers may want to have ranunculus blooms for use in exhibits in August horticultural shows and so some of us will attempt to grow them during the middle of the summer, even though the temperatures are usually hot at that time. Soaking and planting the tubers in early June will provide the correct timing to produce August blooms, but the plants may not produce many if the temperatures — both night and daytime — are too high. Moving the containers to a cooler, shaded location midday may provide the plants with enough relief from the heat to encourage them to produce bloom.
Ranunculus tubers can be stored for the winter. Let the foliage dry off in the fall (protect the plants from exposure to frost), then store the tubers in a cool, dark place in peat moss. Then you will have some healthy ranunculus tubers to start early next spring, providing you with their exquisitely beautiful double blooms.
Albert Parsons writes from Minnedosa, Manitoba.