Bulbs that bloom in the spring (tra-la)

ON GARDENING

Pregnant Onion (Albuca bracteata) According to PlantzAfrica, it is “a clump-forming bulbous geophyte with green and white flowers on tall stems during summer, the common name pregnant onion is derived from the onion-like appearance of the bulbs and they way they form many small bulblets on the side of the mother bulb. The flowers are scented but with an unpleasant smell, white with a broad green central brand (midvein), and a long tapered bract up to 40 mm long with a diameter of about 5 mm.”

Tumbleweed Onion (Allium schubertii). Also called Ornamental Onion, this bulbous perennial grows to a modest 12 to 24 inches tall and has an impressive display of rose-purple flowers in giant, spherical umbels up to 12 inches in diameter. It is native to the eastern Mediterranean area and central Asia. PHOTOS COURTESY TOM KARWIN

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Bulbous garden plants are a category of geophytes, terrestrial plants with their growing points below ground on structures such as bulbs, corms, tubers or rhizomes. Bulbs have tricky characteristics, so today’s column digs into the topic before the timing issues. (Our title refers to a piece from the Gilbert & Sullivan opera “The Mikado,” which can be enjoyed at https://tinyurl.com/2vwkp6tc.)

Our photo gallery features a selection of bulbous plants in my garden.

Bloom times

Bulbous plants are often grouped by their bloom times.

Spring flowering bulbs (Tulips, Daffodils, Crocuses, Hyacinths, Alliums) should be planted in the fall because they need the cold season to start their biological clock. Bloom times occur at different times within “spring,” including early, mid, late, and very late spring and even early summer.

Summer flowering bulbs (Dahlias, Begonias, Gladiolas, Callas) should be planted in the late spring. They will bloom a couple of months later. In gardens in the Monterey Bay area, they will rebloom the following year. In cold climates, however, they should be listed and stored for replanting in the next season.

Autumn flowing bulbs (Autumn Crocuses Colchiums) are planted in the summer.

Spring flowering bulbs

The coming fall weeks are a good time to plant spring-blooming bulbs.

Many spring-flowering bulb plants grow well in gardens in the Monterey Bay area’s temperate climate. The website of Brent & Becky’s mail-order nursery includes an archive of spring flowering bulbs that will succeed in this area’s Zone 9 climate. To access this helpful category of plants, visit https://tinyurl.com/4yc73zwd. This list includes out-of-stock plants, but most can be ordered. Other sources are listed below in this column.

Brent & Becky’s archival list includes a few tulip cultivars that these expert growers advise will grow in this area. One of the Tulip varieties listed as “pre-cooled” presumably would be cooled before shipment by the nursery.

Zone 9 gardeners who enjoy a wide variety of Tulips or other bulbous plants that require a chill period should lift the bulbs after the bloom period and place them in a cooler (34-45 degrees, not a freezer) for six to 12 weeks before re-planting. Some mail-offer nurseries offer pre-cooled bulbs.

As mentioned in this column, we enthusiastically purchased several Tulips long ago at the Netherlands’ Keukenhof Gardens, and almost all failed in our temperate climate. One cultivar (Tulipa ‘Peer Gynt’) has rebloomed regularly, year after year. This uncommon hybrid is no longer on the market. We lifted the bulbs for re-planting this year, and that project is scheduled for the coming weeks.

Landscaping with bulbous plants

Spring flowering bulbous plants can be effective in containers or the ground, in a grouping of one variety, or by combining with plants of complementary or contrasting characteristics. They work well in many different settings.

These plants are available in an impressive range of bloom periods (already mentioned), blossom colors, and mature sizes ranging from 6 inches to 6 feet.

Gardeners inclined to develop their bulb planting in detail will discover value in Brent & Becky’s archive (listed above), which supports searches by bloom time, color, overall size and other variables.

Planting or replanting bulbs

Most bulbs suitable for this area’s moderate climate will propagate independently and can be left in the ground to rebloom in the following season. After a few years, however, the bulb becomes crowded underground, and the plants have fewer blooms.

This process occurred with the large and growing number of Daffodils (Narcissus ‘Mon Cherie’) in my garden’s long parking strip. The task involved lifting hundreds of bulbs, excavating the beds to a six-inch depth, re-planting the bulbs about six inches apart, and replacing the soil atop the bulbs. Gratefully, my gardener did this work, and the plants bloomed well in the following spring.

If you have planted bulbous plants in your garden in previous years, consider lifting and replanting them after three or four seasons for best results.

When purchasing bulbs from a garden center or nursery to add to your garden, installation is a straightforward process. Here are the basic steps, edited from Brent & Becky’s website.

Inspect your bulbs. Small nicks, loose tunics, or blue/gray mold are not of concern, but white mold and soft, lightweight bulbs with a strong, moldy smell should be returned to the seller.

Plant the bulbs promptly. If you need to delay, remove them from the box or crate and store them in a dry, well-ventilated area.

Select a location with well-drained soil rich in humus, compost, or other organic materials. Lighten heavy soil with any good organic material. Raised beds are helpful to ensure good drainage.

Ensure exposure to full sun because, for most bulbs, photosynthesis helps the flowers rebloom the next year. When trees or shrubs grow to shade your bulb plants, prune the branches to let in more sunlight.

Plant the bulbs “pointy-side up.” If the tops and bottoms of bulbs are difficult to determine, plant the bulb on its side!

Applying a top-dressing of compost over the newly planted bed, water at least once after planting and about once a week in the spring unless your garden receives half an inch of rain per week during the growing season.

Sources of spring flowering bulbs

Our local garden centers are not yet offering their full range of choices of bulbous plants for installation in the fall. They will soon have good options for selection.

Mail-order nurseries typically have a broad range of plants, particularly for gardeners seeking uncommon varieties, and some will offer bulk quantities for gardeners planning larger-scale installations.

Brent & Becky’s mailorder nursery (brentandbeckysbulbs.com) is a good resource, but there are others to consider.

K. van Bourgondien (www.dutchbulbs.com) is a wholesale source for flower bulbs, offering a tiered pricing system that provides savings on bulk flower bulb orders.

Breck’s (www.brecks.com/category/Spring_Flowering_Bulbs) also has been in business for many years, offering a broad selection of garden plants.

The California Native Plant Society’s Calscape website (calscape.org) is a resource for gardeners focused on California native plants. This online plant database does not support a search of “bulbs” but produces lists of plants by genus. For example, a search for “Allium” generated information on 70 Alliums native to California, including links to nurseries that offer each plant. Very rare varieties are not currently offered by nurseries, but those offered could contribute to a thematic bed devoted to California native Alliums!

Enjoy bulbous plants in your garden.

Tom Karwin is a past president of Friends of the UC Santa Cruz Arboretum and the Monterey Bay Iris Society, a past president and Lifetime Member of the Monterey Bay Area Cactus & Succulent Society, and a Lifetime UC Master Gardener (Certified 1999-2009). He is now a board member of the Santa Cruz Hostel Society, and active with the Pacific Horticultural Society. To view photos from his garden, https://www.facebook.com/ongardeningcom-5665117 63375123/ . For garden coaching info and an archive of On Gardening columns, visit ongardening.com for earlier columns or visit www.santacruzsentinel.com/ and search for “Karwin” for more recent columns. Email comments or questions to gardening@karwin.com.