Most bulbs bloom as well in the Santa Clara Valley as they do in other parts of North America, but do not necessarily regenerate to bloom after the first year. Endemic soil and climate are unfortunately not very conducive to a healthy dormancy cycle. (Bulbs, corms, tubers and tuberous roots are very different structures but are commonly known collectively as "bulbs.")

Many bulbs should be dug and stored when dormant to minimize rot. Some of the more resilient bulbs, such as narcissus, grape hyacinth and freesia, may regenerate and bloom reliably without this procedure. Many of the more discriminating bulbs, however, such as tulip and hyacinth, are used as annuals to bloom once during spring, then abandoned or removed. Such bulbs may or may not bloom in the future if abandoned, but they are not reliable.

Foliage that remains after the bloom sustains the bulb as it replaces itself with a new bulb. It should therefore be left intact until it abscises from the bulb when regeneration is complete. Developing seed or fruit should, however, be removed because it utilizes considerable resources that might otherwise be stored in the bulb. Seed of some bulbs may likewise become a nuisance by maturing into "feral" seedlings that do not resemble the parents. Feral freesias, for example, typically bloom with small white and purple flowers that are not nearly as colorful or fragrant as their hybrid "parents."

Foliage of bulbs that have already bloomed may be laid flat to the soil surface and obscured by annuals or ground cover. Gladiolus that bloom later during summer do not easily lay flat but fortunately abscise foliage soon after bloom. I would not normally discuss these procedures this early, but so many types of bulbs have been blooming prematurely.

Potted bulbs that have been forced into bloom are more seasonal during winter and early spring, but are unfortunately not easily recycled. Even the most reliable paperwhite narcissus exhaust their resources by blooming in an environment that is not conducive to regeneration of new bulbs. Blooms that appear this year were initiated during the previous growing season while the bulbs were "fattened up" for optimum performance. During and after bloom, new bulbs would normally grow and store resources for the following year. However, bulbs forced in the home lack necessary exposure to sunlight and are unable to disperse roots to adequately sustain regeneration of new bulbs.

Such bulbs are typically discarded after bloom because they will not bloom the following spring—if they survive at all. My neighbor regularly brought home various forced bulbs from work, including Easter lilies, rubrum lilies, tulips, hyacinths, Dutch iris and freesias. Most did not recover in the garden, but some did. In fact, the rubrum lilies have multiplied and are now quite numerous.


Flower of the Week: Nemesia

I think that my colleague, landscape designer Brent Green, used nemesia, Nemesia strumosa, to obscure daffodil foliage at the home of a favorite client in San Luis Obispo. Nemesia is useful as a cool-season annual that performs well through mid-spring while the weather is cool. Mature specimens are usually less than a foot tall but exhibit abundant 3-inch-long floral spikes. The half-inch-wide flowers may be any color; some exhibit two colors.

The delicate, lanceolate foliage may be slightly serrated. Seed can be sown in full sun as early as autumn if sheltered from frost. Soil should be rich and regularly moist but not saturated. Small nemesia is available in six packs (jumbo packs or cell packs) during late winter but is not as common as more typical cool-season annuals.

Horticulturist Tony Tomeo can be contacted at 408-358-2574 or at LGHORTICULTURE@aol.com.