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GARDENING WITH NATIVES

MAY 7, 1992

The meeting was held at the home of Jean Struthers, and included a tour of her lovely garden. Our topic was "Growing Native Bulbs," with bulb grower, C. H. Baccus, known to native bulb aficionados as Chuck or Charlie. He grows many species of native bulbs at his nursery in San Jose. Our talk focused on the Calochortus species, and the Brodiaea complex, since these generally do very well in the hot, dry south Bay climate. (Regarding taxonomy of the Brodiaea Complex, please see reference citation at the end of these notes.)

We tend to think of native bulbs growing in quantity in a meadow-like setting. However, they can be very effective used as accents, much like grasses, with rocks, etc. For a mass of bulbs, gardeners are encouraged to grow their own, either from seed, or offset bulblets. We discussed these methods in more detail.

Some bulbs, grown from seed, can bloom in as little as two years. Over time, some Brodiaea types, such as Brodiaea pulchella (Dichelostemma capitatum), can become weedy in the garden, incredible as that may seem. In such cases, a gopher or two might actually be an asset. Gophers relish native bulbs, as do rats, mice and other rodents. Such predators can cause disaster for the person who is just getting started on native bulbs, or who is trying to propagate and nurture some of the more difficult species. In such cases, bulbs planted in the ground can be protected with wire mesh baskets in the planting hole. Chicken wire is not strong enough to withstand the teeth of some rodents, and it also can rust out. Use 1/2" wire mesh.

Dichelostemma ida-maia is easily grown from seed. The Fairy Lantern Calochortus species can also be grown from seed, which is collected from June to July. The seed pods should be straw colored. With the Mariposa group of Calochortus, the pods should be split at the top. Seeds may not ripen in pods that are partly green.

Calochortus albus, and its variety, rubellus were discussed. They can vary from white, to blush pink to deep rose red. Color changes can occur from year to year in a single population. Charlie is not sure what causes this, but it is likely environmental -- changes in mineral content where they are growing, etc. In any case, you cannot always tell what color your seedlings will turn out to be.

Sow most seed in the fall, though this depends on where it was collected. Stratify those from cold winter areas. Charlie puts them in a moist, sterile mixture of perlite and peat, and uses a solution of Captan on the batch before putting it into the refrigerator, where the standard temperature is 33 degrees. Stratification times vary according to species. An example given was Fritillaria recurva, which has a rather long stratification period of 60 days. This mimics its natural growing conditions. When the seeds begin to germinate, Charlie removes them from the stratification flat with a spoon, one at a time. They are rinsed briefly in water containing a small amount of Super-Thrive, and then placed in the planting box, and covered with 1/4" of the planting medium.

Charlie plants his bulb seeds in wooden boxes 18" x 24" and 8" deep. He uses a mixture of loam and organic matter, with 1/2 C. each bone meal and blood meal per box. No other plant food is used. The medium must not stay too wet, or get too dry. He plants about 50 seeds in one of these boxes. They can be transplanted from the box in about three years. As the plants are growing, watering should follow natural cycles. This usually means one should stop watering around Easter, and resume watering in the fall, whenever green new growth appears.

When seeds cannot be planted right away, they can be stored in the refrigerator, and kept dry. Charlie uses a calcium chloride dessicant for this purpose. When working with bulb seed, you will find that seed of different species varies greatly in size. For example, Calochortus vestae, and C. clavatus have large seeds, while some others are quite small. Even after bulbs have formed, some high elevation species may need to be treated like Tulips and chilled each winter. Clearly, you will have better luck with bulbs from your local climate zone.

After three years in the box, plants can be moved into the ground or into 5-gallon pots. The large pot provides more uniform moisture and temperature than does a small container. As the plants mature, they can re-form their bulbs at a shallower or deeper level than the one at which they were originally planted. They go down when they are seeking moisture, or up with seeking a drier level. This behavior provides clues about the conditions each species prefers. Calochortus plummerae and C. splendens like to grow deep down, while C. amoenus and C. albus like to grow more shallowly in a leaf-mold situation. Some Calochortus form bulbs in the leaf axils. This can be a response to too much moisture, but for some species, it is just standard behavior. Bulbs should be dug up in the fall for transplanting.

The box method allows for more controlled growing conditions, but bulbous plants will actually grow faster in the ground. The Brodiaeas, however, do not do well in a planter box. They should be sown directly into the ground. They will produce bulblets around the main bulb, and at the root ends. Brodiaea terrestris makes bulblets, and B. hyacinthina probably does also. Calochortus species do not produce bulblets as prolifically as the Brodiaeas, nor do they do so in the same way. Sometimes the bulb actually splits, and some Calochortus produce bulblets only under stress. C. uniflorus is extremely prolific in producing bulblets. C. vestae is somewhat prolific.

More mature bulbous plants, especially those grown in pots, can be given supplemental plant food. Charlie has used Fish Emulsion, which, being rather weak, is safest. This can be applied with a "hose-on" sprayer attachment. He has also used a 15-15-15 solution of Ammonium Phosphate applied once a year in the fall. This granular form can be applied at a light rate with a lawn spreader. Calcium nitrate applied in the spring caused deformation in the plants. Pelletized food, such as Osmacote, does not work in the fall, since they tend to be heat activiated. Manures contain harmful fungi, so should be avoided. Charlie has used a two-year old homemade compost, but treated it with Vapam first. This dangerous chemical is definitely not recommended. Composts can be heat- treated in such a way as to destroy the harmful microorganisms, while preserving the beneficial ones. The temperature must be kept under 180 degrees.

Being a commercial grower, Charlie has problems that we home gardeners might not encounter. He has, at times, wanted to kill not only harmful organisms in the growing beds, but rampant bulbs as well! Steaming the beds was a good surface treatment, but did not kill off material deep down. It is hard for growers to comply with well-meant, but unwieldy new pesticide regulations. Growers must go through complicated processes in order to use chemicals which are available to home gardeners with no restrictions. While it is now more difficult to legally use chemicals to control diseases in bulbs, the export regulations on bulbs (for disease control) have become stricter. Chemical fertilizers may be next to come under new, complex restrictions. Anyone thinking of starting a nursery, take heed!

We examined and compared the flowers of several species. In the Calochortus species, the gland at the base of each petal can be important keying characteristic. C. superbus can be yellow, but we saw a white flowered specimen. It has an inverted v-shaped gland. In C. luteus, the gland is an inverted crescent moon, C. vestae has an inverted w, and C. venustus has a squarish gland. There was no such distinctive gland shape in the delicate pink C. spendens (it likes to grow 9" deep in clay). We saw a lovely, large inflorescence of the yellow Bloomeria crocea, and three Triteleias. T. laxa, the well-known Ithuriel's Spear, is variable in size and blooming time. T. appendiculata, also found locally, is similar to T. laxa, but can be distinguished easily by its yellow ovary. We also saw the lavender T. multiflora (Dichelostemma multiflorum). Brodiaea elegans resembles T. laxa, also, but differs enough to have remained in the genus Brodiaea. It also has bigger flowers and is very showy. The specimen we saw was a pink-purple color, but it is usually a lavender blue.

We learned other tidbits of information, such as the fact that Calochortus umbellatus looks like C. uniflorus except for having a black spot on each petal gland. Charlie has not had much success with Lilium species, which apparently do not like the hot, dry climate. He says Erythroniums, the Fawn Lilies, are fairly easy -- grow them like Calochortus. Allium species reproduce easily, but are relished by a variety of creatures (including, in some cases, humans).

Thanks again to C. H. Baccus for a most informative and entertaining meeting! The compiler of these notes hopes readers will excuse any typographic or taxonomic errors! For more detailed discussion on the taxonomic characteristics of Brodiaea, Triteleia and Dichelostemma, please see the articles by Glenn Keator in The Four Seasons, Vol. 8, No. 3, Dec. 1989, and Vol. 9, No. 1, Dec. 1991.

Our next Gardening With Natives meeting will be held at 7:30 p.m., Thursday, June 4, at Foothill College, Rm. P-66 (in the O.H. Dept. near the greenhouses). Parking at Foothill is now $1.00, paid in quarters to the ticket machine in Parking Lot T. Space is limited in the upper, free lot in O.H. We need to save space there for the speaker, the refreshments person, those with no quarters, and those who can't walk up the hill. Ellie Gioumousis, of Yerba Buena Nursery, will discuss hummingbirds and their relationships with native plants. We hope to see you there!

Copyright 2004 Lori Hubbart. Reproduced here with permission.

July 18, 2006