By Linda Jones.
Spring in a non-native plant garden can be a wondrous time of colorful blooms from bulbs; tulips, ranunculus, daffodils, etc. But what about California native bulbs?
There are over 200 native plants that grow from bulbs, corms or rhizomes, and about 75 are native to at least parts of San Diego County. The variety of bloom styles and colors is amazing. There are various types of lilies and amaryllis, fritillarias and onions, in every color, even chocolate (Fritillaria biflora).
Bulbs are geophytes who developed a strategy to survive drought and fire by storing water or energy below ground. Since carbohydrates are often stored there, the bulbs are a good food source. Some species were managed by Native Americans to provide a reliable food source. Many animals have also discovered tasty bulbs as a food source. So if you have resident wildlife, be prepared to protect the bulbs; dig them up and store them indoors after the bloom or better yet, share with the wildlife.
Bulbs are not always easy to grow or even easy to find in native plant nurseries (for a partial list of mail-order sources check Mother nature’s Backyard https://mother-natures-backyard.blogspot.com). One reason to include bulbs in your native garden is that they are losing ground in the wild due to development, horticultural collectors, grazing and other human activities. Some are important sources of pollen and nectar for butterflies, moths and hummingbirds and seeds for seed-eaters. In planning your garden to help conserve the natural ecosystems, consider adding some bulb species too. You will be rewarded with unusual, beautiful blooms in your garden.
To be successful with bulbs you need to know their preferred habitat: dry, disturbed, riparian, montane. Tolerant of summer water or not? Most species require water during the growing season in order to bloom but prefer little to no water during their dormant stage. Once the bloom has ended and the leaves turn yellow, withhold water. However don’t clean up the dead leaves too soon. Wait until they are brown/dead to ensure the maximum transfer of energy to the bulb for next year.
One reward of growing these plants is that some species produce new bulblets or cormlets each year and therefore slowly expand their area in the garden, at no cost or effort to you. Some species however need to be grown from seed and then you need patience as it can take 2-3 years before they produce bloom.
A good starting plant for introducing bulbs in your garden are Blue Dicks or Wild Hyacinth (Dichelostemma capitatum, Brodiaea family). It is widely dispersed in many natural communities including grasslands, open slopes, coastal sage, open areas in the chaparral and forests from Oregon to northern Baja California and inland through the Southwest. It can be abundant after wildfires.
Blue Dicks' are easy to grow and can be found in at least some native plant nurseries. It forms small, tight clusters of lilac or blue-violet bell-shaped flowers on long leafless stems from February to May. It is adaptable in soil type BUT it will die if watered in summer after it finishes blooming and enters its dormant stage. With winter rains Blue Dicks will reappear and bloom. The plants are 6-10 inches tall but the flower stalk can be seen nodding up to 3 ft high over other plants.
The plant naturalizes quickly but is beloved by gophers, rabbits and even birds, so you may want to protect the corms from these marauders.
Predation is actually a strategy used by the plant to survive and spread. As the predator digs for the corm, the new cormlets attached loosely to the corm are scattered and grow into new plants the next year.
Blue Dicks were an important food source for Native Americans in California. The corms were harvested either in spring or after seeds were shed. The cormlets were then replanted for harvest the next year.
Left: Ithuriel's Spear. Triteleia laxa, © Calscape. Photo taken at Rancho Santa Ana Botanical Garden.
A bulb that is easier to find in nurseries is Ithuriel’s Spear,Triteleia laxa, also in the Brodiaea family. It occurs naturally from southwestern Oregon through much of northern and central California. Although it is not native to the San Diego area, it is a good choice in our gardens with blooms in white, purple or blue-violet. I grow the blue-violet form in a pot of standard garden soil but it will also tolerate heavier soils. It is also tolerant of my lackadaisical gardening care and importantly of moderate summer water.
Right: The threatened Lemon Lily, Lilium parryi, in Idyllwild, CA Mountains. Photo from https://alchetron.com/Lilium-parryi
One of my favorite lilies, even though I cannot grow it in my lowland area, is the Lemon Lily, Lilium parryi. It is native to the Southwest and northern Mexico but has a very restricted range, occurring only in scattered moist patches in mountain areas above 4000ft. In San Diego County, it is limited to a few patches on Palomar Mountain. It is the beautiful deep lemon-yellow, fragrant flowers that make it worth seeing. If you want to see it in bloom, head to Idyllwild, CA for the annual Lemon Lily Festival in June (in non-covid years). The Festival promotes the restoration and conservation of this beautiful lily which is listed as threatened in the wild.
Although bulbs are not always the easiest plant you could grow, they are worth considering for their value in the ecosystem, the beauty of their bloom and their willingness to give you new plants each year.
Linda Jones is a member of the Master Gardener Association of San Diego. She has a special interest in preserving our native plants and ecosystems, especially in our gardens.