We’re enjoying a banner bulb season. Here’s how to keep these annuals at their best

Spring-flowering bulbs are finishing a spectacular bloom season here in the central San Joaquin Valley. Cooler, wetter weather this spring has kept flowers alive and looking fresh for several weeks longer than in the past dry years.

As bulb flowers fade, cut them off but leave the foliage to brown and die back naturally. The green leaves provide food for the bulbs and help ensure another bloom season next year. A tablespoon or two of bulb food or bone meal sprinkled over the dying foliage will provide phosphorus necessary for increasing bulb size.

Narcissus, leucojum (snowflakes) and daffodils naturalize or reproduce offsets and spread easily. If your bulbs have formed a large clump of leaves with fewer flowers, dig the bulbs up after the foliage has browned, separate the individual bulbs and replant them or donate them to friends and neighbors. After a rainy winter and spring, our soil is more workable. Replant bulbs at same depth (two times the length of the bulb) and add bone meal or bulb food to the bottom of the hole. Water well after replanting.

While you’re digging in the garden, consider planting summer- and fall-blooming bulbs, corms, tubers and rhizomes. There is a large variety of color and size within species of perennial summer and fall bloomers including calla lilies (rhizomes), lilies (bulbs), dahlias (tuberous roots), begonias (rhizomes, tubers), gladioli and crocosmia (corms). Foliage plants including brightly colored, patterned and textured Rex begonias (rhizomes) and caladium (tubers) fill in shady spots beautifully.

Most bulbs, rhizomes, corms and tubers are not drought-tolerant so keep the soil consistently moist all year. Dig deep holes and add organic matter such as compost and humus to the soil when planting to improve water retention and drainage. Our intense summer heat does shorten bloom time. Provide afternoon shade for all types and plan on moving hanging baskets and pots of begonias into dappled light in summer.

Bulbs contain an embryonic plant within a papery covering, called a tunic. Roots grow from the broader bulb bottom and leaves and flowers grow from the top. The bulb is composed of scales that are modified overlapping leaves.

Lily bulbs do not have a protective outer covering and will dry out quickly. Plant lilies immediately after buying them. Lilies have strong, erect stems that can grow to six feet tall in some species. Plant lilies where they’ll be sheltered from the wind and place sturdy stakes into the soil when planting.

You might need to stare at the calla lily rhizome for several minutes to determine which end is up; the end with stem remnants is the top. Common Calla lilies die back and disappear during hot weather but will reappear and rebloom next season. Golden callas can tolerate full sun.

Corms look similar to bulbs but they are solid inside with no leaf scales. The flat bottom plate will produce roots and the slightly pointy top is the growing tip. The original corm will die after one year, but will produce small offsets that can be removed and replanted when flowering slows after a few years.

Tuberous dahlia roots should be planted flat in well-amended soil and covered with 3 inches of soil. The fleshy roots are true roots that store water and nutrients.

Tubers look like corms but they have multiple growth points over the entire surface (like potatoes have eyes). Begonia tubers are perenials (unlike potatoes) and grow larger every year.