Ranunculus Bloom Season in California

Common Blooming Season

• Spring is the main blossoming season for ranunculus in California. A transplant or tuber must be planted in the fall for an early spring flowering -- ranunculus grow from tubers, often mistakenly identified as bulbs. Ample water applied to the soil immediately after planting, along with a layer of mulch, provides ideal conditions for root formation. For example, October or November plantings allow tubers to grow sufficient roots for blooming in March. Although each variety has a different flowering period throughout the spring, some varieties bloom all the way through August in proper conditions. In general, choose the largest tuber you can find for prolific flowering possibilities.

Considering Planting Times

• If you live in USDA zone 7 or cooler, alter your tuber planting time to early spring rather than fall. In these colder California regions, frost could damage the tubers over the winter even if they are planted at an ideal 2-inch depth with their pointed ends extending downward. Place them in the refrigerator for up to 2 months during the winter to provide a safe chilling period for blossom stimulation. In USDA zones 8 and higher, plant them in autumn because the winter provides a natural two-month cooling period to stimulate sprouting. However, any unseasonable heat waves throughout the winter can cause blooming failure as the ranunculus detects summer conditions and enters dormancy.

Flower Encouragement

• With blossoms that last nearly two months in spring and summer, tubers need to recharge their energy reserves for next year's flowering. Cut the spent flowers away to avoid having energy wasted in seed formation. However, allow the fading foliage to remain on the stem until it is completely yellow, because ranunculus continues to photosynthesize until the chlorophyll is spent within the leaves. Although the leaves might look unsightly without a burgeoning blossom, this energy production and storage period provides the tuber with the ability to return next year with huge flowers in USDA zones 8 and higher. Treat these bulbs like annuals, however, in cooler USDA zones 7 and lower.

Failed Blossoming

• The California bloom season will fails to provide lush flowers if the garden bed is not created and maintained correctly. When planting ranunculus tubers, choose a full sunlight location that offers well-drained, nutrient-rich soil. Good soil drainage prevents tubers from rotting in wet conditions -- ranunculus needs a damp environment, not a soggy habitat. Flower development requires critical soil nutrients along with ample moisture, so till organic matter into the bed before planting the tubers to provide elemental nutrients and good soil texture.