Our Climate Is Ideal for S. African Flowers

Question: What South African bulbs do you recommend planting in Southern California? Are there any that will naturalize, and what conditions do they require to thrive?

R.S., La Habra

Answer: Southern California’s Mediterranean climate--winter rainfall and summer drought--provides the conditions South African bulbs prefer. Such bulbs generally bloom in late winter and spring, but should be planted now through early fall.

South African or ‘Cape bulbs’ thrive in a variety of situations, but two things are required to grow them: good drainage and little to no summer water.

To grow South African bulbs follow these guidelines:

* Choose a site with excellent drainage, whether it is a pot, raised bed, mounded area or slope. If you grow the bulbs in a pot, you can move the container to a hidden spot once they finish blooming to lie dormant and multiply.

Plant them in clumps of five or more for added impact. Jim Duggan, owner of the Jim Duggan Flower nursery in Encinitas, which specializes in South African bulbs, recommends the following sand-based planting method for all South African bulbs.

* For ground and container planting, use a mixture of about 40% compost (a bagged potting mix works fine for pots), 40% coarse sand and 20% pumice.

* Fill containers to the desired planting depth with the potting mix and pumice mixture (pumice aids drainage). You may also want to add a small amount of bonemeal. Next, add a half-inch layer of coarse sand (builder’s sand is preferable to play sand).

Place the bulbs on the sand base and cover completely with more sand. Fill the remainder of the container with potting mix.

* Plant South African bulbs in August to a depth of two to three times their height, but do not water until early October. All Cape bulbs should be planted by the end of October. If any begin to sprout, plant and water them immediately.

* The majority of South African bulbs prefer full sun, but in hot inland areas a bit of shade is good. Some, such as Cyrtanthus, Geissorhiza, Gynandriris, Hesperantha, Lachenalia, Massonia, Moraea, Polyxena, Romulea and Veltheimia, do best in 30% to 50% shade.

* Begin watering in early fall. Water deeply, but let the soil dry out between irrigations. When forming leaves, they should be watered frequently; a bit less after they are grown, and not at all when they are dormant.

Duggan recommends watering once a week with occasional extra water if it is warm. After they finish blooming, the leaves will begin to yellow, signaling the onset of dormancy. Do not remove the dwindling foliage, because the bulbs are storing energy for next year’s growth.

When the leaves have completely withered, cease watering entirely. At this point, once the soil has dried completely, if in pots, store them in a shaded location.

* Once bulbs start to grow and leaves emerge, feed with a low-nitrogen, 100% water-soluble fertilizer. Feed them every three to four weeks until they finish their bloom cycle.

* Some South African bulbs are poisonous, while others such as Watsonia can fall prey to gophers and ground squirrels. Use appropriate control or plant in a heavy-gauge wire-mesh basket.

Choice of Bulbs

There are numerous species of South African bulbs to choose from (those noted to tolerate some summer water must have excellent drainage):

* Babiana. This species naturalizes quite readily. Most of the flowers in this group are 12 to 16 inches tall and lavender blue, but are also available in white, yellow, red and assorted variations of these colors. Flowers in March. Members of this genus said to be more tolerant of summer water are B. disticha, B. pulchra, B. stricta and B. vilosa.

* Freesias. Freesias will naturalize if undisturbed. They average 12 to 18 inches tall, are good in containers, trailing over the edge of hanging baskets, and cast a wonderful fragrance along walkways. They come in shades of yellow, blue, red, pink and white as well as bicolors. They are easy to grow, make great cut flowers and bloom over a long period.

To minimize their tendency to flop over, grow in full sun, in pots for support or if planted in the ground, plant close together. You may want to consider the Tecolate hybrids that have been developed to have shorter, stronger stems to hold them erect. They bloom in spring.

* Gladiolus. These cape bulbs are far more graceful than the common gladiolus cultivars of which we are most familiar. Many of them look like baby orchids. One pale yellow species, Gladiolus tristis, has fragrant blooms, makes an excellent cut flower and will tolerate some summer water. Blooms in March and April.

* Homeria. These cape bulbs come in vivid shades of lime, orange, and salmon. They average about 2 to 2 1/2 inches tall. Many will tolerate some summer water, such as H. collina, a pastel coral orange, H. flaccida, a coral orange with yellow throat (both can naturalize), and the profuse bloomer, H. ochroleuca (lemon yellow). They flower in March or April.

* Lachenalia. You may want to consider growing Lachenalia in pots, as they require excellent drainage and no summer water. They prefer 30% to 50% shade and most come in shades of pale blue, lime, cream, with several in bolder colors such as mustard and turquoise. They average 1 to 1 1/2 inches in height, and make good cut flowers.

* Romulea. If allowed to dry out in summer, these bulbs can naturalize quite well. They produce abundant star or cup-shaped blooms and do best under 30% to 50% shade. Ranging in color from white to yellow, orange, apricot, pink, even blue and bright red, they average about 1-foot tall with chive-like foliage. Ideal in containers.

* Sparaxis. Also known as the harlequin flower, this comes in numerous shades of orange, red, white and yellow, often with a bright yellow center and black outline. Sparaxis naturalize easily and make excellent cut flowers. According to Duggan, Sparaxis Tricolor and hybrids and Sparaxis bulbifera will tolerate some summer water. They bloom over a long period in late spring.

* Tritonia. These cape bulbs have delicate flowers in shades of pale yellow, salmon, coral, peach, pink and orange. They bloom 12 to 18 inches above grassy foliage and last a long time as a cut flower. T. Crocata (pale peach to orange) and T. lineata (cream blooms) can tolerate some summer water. T. lineata naturalizes well.

* Watsonia. This genus closely resembles the Gladiolus, but the plants are generally taller with smaller more graceful flowers. Dwarf varieties, which reach 2 feet or so, are perfect in pots. The taller varieties to 3 feet tall are great as background plantings with perennials. They bloom in late spring and early summer in colors of white, pink, rose, lavender, orchid and mauve and make good cut flowers.

Watsonia beatricis, an evergreen species, is also available. It reaches 3 to 4 inches tall and blooms in shades of salmon, coral and orange. Most watsonia varieties will tolerate some summer watering if drainage is very good.

Sources

There are a variety of resources for obtaining South African bulbs.

* UC Irvine Arboretum has have an annual South African bulb sale Aug. 28.

* Jim Duggan Flower Nursery in Encinitas, (760) 943-1658. South African bulbs can be obtained through mail order. An order form can be downloaded from the Web site at https://www.the bulbman.com. This web site also has pictures of all the species of South African bulbs he has available.

* Many local nurseries will have an assortment of bulbs now.

Have a problem in your yard? University of California Cooperative Extension (UCCE) Master Gardeners are here to help. These trained and certified horticultural volunteers are dedicated to extending research-based, scientifically accurate information to the public about home horticulture and pest management. They are involved with a variety of outreach programs, including the UCCE Master Garden hotline, which provides answers to specific questions. You can reach the hotline at (714) 708-1646 or send e-mail to ucmastergardeners @yahoo.com. Calls and e-mail are picked up daily and are generally returned within two to three days.