Best bulbs for Sonoma County’s drought-prone climate

As the drought lingers and our water use is strictly measured, plants that will grow without additional irrigation beyond what they get from rain have become increasingly appealing.

We read a lot about perennials and succulents. But what bulbs can thrive in our summer-dry, drought-prone climate?

A number of bulbs, or geophytes, need no additional watering, and some are native to California. Geophytes are plants with underground storage units that store water and carbohydrate resources, or energy. They include bulbs but also plants with corms, tubers or rhizomes. Bulbs are made up of layers of scales, modified leaves, really. Onions are a familiar example and illustrate on a large scale the structure of many bulbs.

Geophytes typically come from areas that have short, intense growing seasons such as arid or even alpine regions. During the growing season, they emerge from dormancy underground and put out leaves and eventually flowers. After flowering, as soil dries and growing conditions decline, leaves die back and the bulb enters a dormant period, basically “sleeping” through unfavorable conditions. It remains in this state until rains wet the soil and signal a new season for growth.

Look to Mediterranean, South Africa

Besides our native bulbs, there are a number of bulbs from the Mediterranean region and South Africa that are adapted to our summer-dry climate. These emerge from dormancy in the late fall or spring, flower in the spring or early summer, then die back and basically disappear for the rest of the season

Most bulbs prefer well-drained conditions, but some tolerate clay. Sun is best for many. To display some of the smaller bulbs well, grow them in weed-free conditions. The smaller bulbs also do well in pots. Larger and more robust bulbs like daffodils and narcissus can more easily compete with weeds.

The best time to order bulbs is in the summer, typically when planting bulbs is far from our thoughts. Many bulb companies offer discounts for summer orders. Bulbs are shipped in fall or early winter and planted right away. Fall ordering has far less availability, but don’t let that stop you from trying. Just make a note to shop earlier next year. Also, some area nurseries offer young potted plants in spring.

Overlooked, exquisite natives

Underrepresented in gardens yet so easy to grow, our native bulbs are some of the most exquisite and interesting of all. A favorite is the firecracker flower (Dichelostemma ida-maia), with glistening crimson-rimmed chartreuse flowers dangling at the end of long, slender stems. Wonderful as multiples in a pot or in the ground, it is guaranteed to generate interest and is fairly easy to find in bulb catalogs.

Triteleia (they used to be called Brodiaea) are common native bulbs often seen in grasslands or on rocky banks, with clusters of upright tubular blue-purple flowers.

‘Queen Fabiola’ is another popular selection and is usually available from bulb catalogs. Area nurseries sometimes carry them in pots. Some native onions (allium) are available from bulb catalogs or area nurseries that specialize in native plants. With a low stature and showy deep pink-mauve flowers, these are wonderful in a pot or in a rock garden.

Mariposa lily (Calochortus) are one of the last native bulbs to flower. They bloom in May and June, when soil and grasses are drying, and resemble an elegant upright poppy at the end of a slender, almost leafless stem. The four petals are one color, often pink or white, but the interiors can be strikingly marked like a butterfly wing, which they are named after. Some standard bulb catalogs carry them very inexpensively.

A wonderful online resource for native bulbs is a small company based in Ferndale called Telos Rare Bulbs (telosrarebulbs.com or email telosrarebulbs@suddenlink.net). They have an incredible selection of native, South American and South African bulbs and other rarities. Perusing the photos on the website is like looking through a jewel box of botanical wonders.

Some spring-blooming South African bulbs (technically corms) which are fairly easy to find and grow are freesia, ixia and sparaxis, all which grow best in weed-free conditions. Freesia are small bulbs with short spikes of fragrant, cascading flowers. They come in white, cream, purple, red and yellow. Some of the more brightly colored selections have lost their scent, but recent introductions have a strong fragrance. Freesia spread nicely in gardens throughout the Bay Area. They can be grown in a pot or outdoors.

Ixia, or wand flower, come in white, pink, yellow and red. The very showy flowers are lily-like and clustered on a long, slender stalk. Each flower has a contrasting darker eye, often magenta to maroon.

Sparaxis, or harlequin flower, looks like a smaller version of ixia, with even more flamboyant open star-shaped flowers in orange, white, pink or lavender with contrasting centers.

Another easy bulb that tolerates summer-dry conditions is the Spanish bluebell (Hyacinthoides hispanica). They bloom in late spring, before the Calochortus. The long-lasting foliage is as elegant as the bluebell flowers. They can be found in blue, pink or white. Resembling English bluebells, these drought-resistant, summer-dry bulbs appreciate compost and good soil conditions. They do well in shade and sun.

A common bulb that does well and naturalizes in the right conditions is the grape hyacinth. Small in stature but with multitudes of blue flowers, these bulbs don’t stint in terms of profusion. They do well in shade or sun and are available in light blue and bi-colors. They also appreciate compost.

Some species of gladioli, such as the very spectacular Gladiolus carneus, do well with summer-dry conditions, but there are others. Tulipa clusiana and Tulipa acuminata are both recommended for southern regions. They are not the usual big-flowered beauties but have very attractive slender blooms in bi-colors of yellow to red that are very interesting in themselves.

Seeking out these bulbs usually entails looking through bulb catalogs and area nurseries rather than big box stores. Many bulb companies have online and print catalogs. Catalogs serve as a good reference for bulb growing. Here are a couple to check out:

McClure and Zimmerman: mzbulb.com; 800-883-6998

John Scheepers: johnscheepers.com. 860-567-0838

Kate Frey’s column appears every other week in Sonoma Home. Contact Kate at: katebfrey@gmail.com, Twitter @katebfrey, Instagram @americangardenschool.