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Growing Notes: The White Jacaranda

March 29, 2009

Plant Information

George H. Spalding
Lasca Leaves 18:41, 1968.

To the true plantsman few experiences can match the thrill of seeing the first seedlings of a new and unknown plant obtained from some distant part of the world. It requires patience to grow a plant to maturity and give it adequate testing. There is always the temptation to introduce a promising species quickly while initial enthusiasm is high, without waiting for it to reach maturity, or go through a cold winter, or undergo any one of the many other tests required before a plant can be considered ready for introduction.

When a plant has been fully tested and is ready for introduction, propagating stock plants are grown and made available to nurseries at cost of production. Although brief resumes are sent to trade journals when a new plant is released, to date no full account of Arboretum introductions has been published. So from time to time detailed reports of Arboretum plant introductions will appear in Growing Notes to provide a continuing official record.

One of the most interesting LASCA plant introductions is the so-called white jacaranda. This selection is considered a pure white form of acutifolia; however, such an albino variation has not been recorded in the Peruvian floristic literature. This accession, received in 1952, resulted from the efforts of Dr. Russell J. Seibert, then director of the Arboretum. While working in Peru in 1946 he had seen trees of this white form growing at the Agricultural Experiment Station of La Molina in Lima. It was reported at that time to have been introduced into cultivation from wild material found near Huanuco, Peru.

Feeling that this tree had great horticultural potential for Southern California, a successful attempt to obtain budwood was made resulting in the 1952 accession. Eleven dormant sticks were received. It has been reported that this jacaranda had been propagated by cuttings in Peru. The budwood sticks received were of thick caliper and failed to root when treated as cuttings. As soon as it became evident that the cutting method was not going to work, buds were taken and worked onto available rootstock of the typical Jacaranda acutifolia. Two of the budded seedlings “took,” but only one survived. This survivor provided buds for additional propagations two years later.

The original tree at the Arboretum first bloomed in 1957. Its flowers appeared in rather small trusses in this first season, but the color was a good clear white. Flowerings in later years have produced larger trusses, but while occasionally promising, the over-all performance is disappointing. Consequently, bloom has been erratic and not particularly effective. We do not know the reason for this poor performance, but believe it to be physiological in nature, or possibly poor adaptation to this particular region. If the cause can be found and removed, the white jacaranda will become a major addition to our list of outstanding flowering trees.

This jacaranda was offered to the trade through a notice in the Pacific Coast Nurseryman of April 1961 (Vol. 20, No. 4, pp. 20-21).

Thanks are due Austin Griffiths, Herbarium Curator at the Arboretum, for the suggestion that this series be undertaken.

Behind the Scenes

March 29, 2009

Plant Information

A Behind the Scenes Look… Our members and visitors rarely have the opportunity to visit and get a first hand glimpse of The Arboretum’s greenhouses and nursery facilities. The importance of these facilities to the operation of The Arboretum is immense. Our greenhouses and nursery are used to propagate, grow, and nurture plants for the many collections we currently have and future collections still being planned. Plants obtained for the collections may have arrived into the nursery in the form of seeds, vegetative cuttings or live plants. Often the material comes from private collectors, other botanical institutions, and even from native habitats around the world.

Thousands of Plants Grown

There are literally thousands of plants being grown in our facilities. Some, such as the Ceratonia oreothauma, a close relative of the Carob tree, are nearing extinction or, even worse, are now extinct. Often, arboreta and botanical garden nursery facilities have become the Noah’s Ark for the plant world.

Tropical Plants

At the moment, we are working on developing a collection of culturally significant tropical plants that will eventually find there home in our Tropical Display Greenhouse. These plants are now merely pampered seedlings and/or recently rooted cuttings. Once these plants mature, they will be added to the Display House collections.

Orchids

Six of our greenhouses are home to one of the largest collection of orchids in the western United States. With approximately 10,000 plants, this collection is of world-class stature and provides blooming plants that can be seen year around in The Arboretum Rotunda and Tropical Display Greenhouses.

Baldwin Bonanza Offerings Most of the plants propagated at The Arboretum for the annual Baldwin Bonanza Festival of Plants Sale are grown in the Education Greenhouse and Nursery. The Education Greenhouse and Nursery is maintained by volunteers and two interns, however, there is always room for more volunteers! Baldwin Bonanza 2002 propagated plants will be selections from The Arboretum’s outstanding collections.

A Fantastic Staff

Last, but certainly not least, a behind the scenes look would not be complete without mentioning our fantastic staff who take care of these facilities. All of the staff has worked very hard in the past year to bring about significant changes in their assigned areas. Julie Norman is our orchid propagator. Julie also has the responsibility of overseeing all nursery operations, including nursery staff management. David Okihara maintains the Display Greenhouses. Thanh Pham, a student professional worker, has been assigned to the accessioning of the orchid collection. Tanya Finney and Sherry Tobin maintain and manage the propagation nurseries and greenhouses.

Behind the Scenes Tour Planned

Those interested in learning more about the greenhouses and nursery facilities will be able to get a behind the scenes tour this winter when the days are cool and memories of 100 degrees have long since past. So, if you long for warmer days during the winter months, a visit to The Arboretum’s greenhouses will certainly warm your spirits. We hope to have a tour date set for the next newsletter. Stay tuned. Timothy Phillips Superintendent

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