Tree with yellow flowers and long seed pods

Cassia fistula 7 Gal

GENERAL DESCRIPTION:

Golden shower is a fast-growing tree of medium size, typically 20-40 feet tall, with an irregular, vase- or oval-shaped crown, which is moderately dense. The branches are well-spaced and slightly drooping. The bark is grey, mottled and moderately rough and may have thorns. Leaves are bright green, 12-18 inches long, alternate, pinnate, with 4-8 pairs of ovate, opposite leaflets each 3-6 inches long; the tree is briefly deciduous. In full bloom, the tree is festooned with chains of golden yellow flowers, 8-18 inches in length, blooms with 5 petals each about 2 inches wide. Flowers are followed by dark brown, cylindricaa seedpods, 1 inch thick and up to 2 feet long, which persist on the tree through the winter. Pods have a pungent odor and contain several poisonous seeds, which are used for propagation. The tree has strong, durable wood. Golden shower grows well on a range of soil types providing they are well drained; it has no major pest or disease problems. It should be pruned to control the crown shape, especially when young. In landscaping, this is a showy specimen tree and is an excellent choice for gardens, for shade and as a street tree. Golden shower is the national tree of thailand.

On the corner of Riverside Drive and Hazeltine Avenue in Sherman Oaks, two pairs of gold medallion trees are in full bloom. If you are wondering how these trees got their name, just take a look at their spherical flower clusters which, from a distance, have the appearance of circular gold medallions, a kind of botanical bling.

As budgets for tree pruning are pinched, gold medallion trees (Cassia leptophylla) are planted more frequently because of their moderate size. Mature gold medallion trees reach a height of only 25 feet. At the same time, their canopy spreads out to 30 feet and thus, in the shade below, you can place a picnic table for having lunch al fresco on a summer day.

Gold medallion flowers, after they fade, are followed by very long chocolate brown pods, which impart considerable ornamental interest of their own. These pods may grow up to 2 feet in length. Kids enjoy shaking them like castanets since the seeds inside make noise as they rattle around. Attractive dark, fissured bark is showcased when leaves drop off, if only briefly, during the winter.

Although native to Brazil and considered a tropical species, gold medallion trees can survive temperatures in the mid-20s and are highly drought tolerant, too. Germinating gold medallion seeds is easy. Pick up fallen pods, split them open and remove the seeds, placing them in a cup or bowl. Boil water and pour it over the seeds. By volume, there should be a ratio of 10 parts water to one part seeds. Let seeds sit in water for 24 hours and plant.

This same procedure can be used for germinating seeds from most leguminous trees. Leguminous trees include carob, coral trees (Erythrina species), acacias, orchid trees (Bauhinia species), black locust (Robinia species), honey locust (Gleditsia triacanthos) and mimosa (Albizia julibrissin). Leguminous trees with extremely hard seed coats, such as mesquite (Prosopis species), may require a dunk in sulfuric acid in order to germinate. While most of these trees are characterized by pinnate foliage, where two rows of narrow leaflets line up opposite each other on the stem, linear and compartmentalized seedpods are common.

An advantage of planting leguminous trees is that they manufacture their own nitrogen with the help of symbiotic bacteria that inhabit nodules in their roots. Thus, leguminous trees are suitable for planting in nitrogen-poor and desert soil.

Black Diamond crape myrtle

There is a new tree on the block that also blooms in July and is worth mentioning: Black Diamond crape myrtle trees. Black Diamond trees are so named on account of their deep burgundy, virtually black foliage. These trees grow to a height of 12 feet and, from what I have seen, are as suitable for hedges as they are for containers and as stand-alone subjects or accents. Black Diamond crape myrtles are also mildew resistant and, in the general manner of crape myrtles, seem to flower most following a dry winter. They are available in several shades of red as well as pink, blush, white and purple.

Crape myrtles of every description, all of which are deciduous or leafless during winter, are best pruned at winter’s end. The reason for this is that flowers are produced on shoots grown in spring. If you prune earlier, new and tender growth could begin prematurely, during a warm spell in February, for example, which could be damaged later on by a sudden freeze.

Fertigation

Ted Howard, whose Flower’d by Howard gardens have long been familiar to San Fernando Valley residents, has adopted fertigation to provide a constant mineral feed to his plants. Fertigation involves the integration of a feeding tank into an irrigation system so that each time water is applied, fertilizer is applied as well. Howard adds bio-stimulants to his fertilizer mix, too.

Howard says that five months ago he was applying 30 gallons of water per day to a 125-square-foot garden of his own, located near Roscoe Boulevard and Coldwater Canyon Avenue. Prior to planting, he amended his soil with 10 cubic feet of ordinary planter mix and water-retaining crystals that acquire a gellike consistency and spongelike quality upon hydration. Since May, thanks primarily to fertigation, he has been able to cut his garden water use by half. Keep in mind that water in Los Angeles costs less than a penny per gallon, so while he was spending around $2 per week to water his garden five months ago, he is spending around $1 per week today. It should be noted that Howard utilizes lengths of drip tubing, set 6 inches apart, to irrigate his garden. Otherwise, his water usage would be significantly greater.

For more information about area plants and gardens, go to Joshua Siskin’s website at www.thesmartergardener.com. Send questions and photos to [email protected]

Cassia leptophylla (Gold medallion tree)

Botanical name

Cassia leptophylla

Other names

Gold medallion tree

Genus

Cassia Cassia

Species

C. leptophylla – C. leptophylla is a tender, open, spreading, semi-evergreen tree bearing pinnate leaves with ovate, mid- to dark green leaves and upright racemes of fragrant, bright yellow flowers in summer followed by long, dark brown, cylindrical seed pods.

Native to

Brazil

Foliage

Semi evergreen

Habit

Open branches, Spreading

Toxicity

Seeds are toxic if ingested.

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Colour

Flower

Bright-yellow in Summer

Green in All seasons

How to care

Watch out for

Specific pests

Glasshouse red spider mite , Glasshouse whitefly

Diseases

Generally disease-free.

General care

Pruning

Pruning group 1 in early spring. May need restrictive pruning if grown under glass. Height may be shorter if grown under glass or in colder climates.

Propagation

Sow seed at 18-21C in spring.

Propagation methods

Semi-ripe cuttings, Seed

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Where to grow

Cassia leptophylla (Gold medallion tree) will reach a height of 7.5m and a spread of 9m after 10-20 years.

Suggested uses

Sub-Tropical, Drought Tolerant, Cottage/Informal, Containers, City, Beds and borders, Wallside and trellises

Cultivation

Under glass, grow in loam-based compost in full light. In growth, water freely & feed monthly. Top dress or pot on in spring. In frost-free areas, grow outdoors in moderately fertile, deep, well-drained soil in sun. Drought tolerant once established. Tends to drop older leaves in winter or drought.

Soil type

Chalky, Loamy, Sandy

Soil drainage

Well-drained

Soil pH

Acid, Alkaline, Neutral

Light

Full Sun

Aspect

South

Exposure

Sheltered

UK hardiness Note: We are working to update our ratings. Thanks for your patience.

Tender in frost (H3), Indoor heated (H1)

USDA zones

Zone 12, Zone 11, Zone 10

Q. I’ve been noticing some flowering trees in a shopping center parking lot that are really nice. They have large clusters of yellow flowers that remind me of giant buttercups. The trees are not very big, although I think they are mature trees. Can you identify them from my description? I think I’d like to plant one if it’s not too difficult to grow.

A. I believe the trees you saw were Cassia trees, either Cassia excelsa, commonly called the Crown of Gold tree, or Cassia leptophylla, commonly called the Gold Medallion tree. Both species of trees produce large clusters of bright yellow flowers in summer. Both have compound leaves with leaflets arranged in pairs along the leaf midrib. C. excelsa has 10 to 20 pairs of leaflets whereas C. leptophylla has 12 or fewer pairs of leaflets. As you have observed, the trees are relatively small in size, with both species typically growing quickly but staying under 25 feet tall at maturity. They usually begin blooming in July and continue through the summer months.

Any time you find plants growing in commercial landscapes, you can be pretty well assured that the plants are trouble-free and tolerant of most growing conditions. Cassias are no exception; they are easy to grow and require only ordinary garden care. The only aspect of their culture that is somewhat unconventional is that they should be pruned in late summer, after they have bloomed, not in the winter, when most plants are pruned. Both species I have mentioned are considered somewhat evergreen, so they always have a presence in the garden.

By examining the number of pairs of leaflets on the trees at the shopping center, you will be able to identify which species of Cassia they are. There are many species of Cassia, but the Gold Medallion tree, C. leptophylla, is probably the most popular species, with the Crown of Gold tree, C. excelsa, being the second most popular. Both are excellent trees for the home landscape and will give you wonderful summer color.

Q. Some of my lemons have multiple points, almost like fingers, at the end of the fruit. Are they mutations?

A. Lemons develop multiple points when they are infested with bud mites. These very tiny sucking insects feed on tender young growth and can cause distorted leaves and fruits. Although they may look peculiar, the lemons usually are still usable. Water stress and dust on the trees can promote increased bud mite populations, so keeping your tree adequately irrigated and free of dust will discourage these damaging insects. Since you can’t count on natural enemies of the bud mite to be in your environment, these simple cultural practices are especially important.

Contact the writer: Ottillia “Toots” Bier has been a UC Cooperative Extension master gardener since 1980. Send comments and questions to [email protected]

Gold medallion tree (Cassia leptophylla). Photographs by Don Walker

Although we do have our tropical moments in Southern California, even our mildest climates are still too cool and dry most of the year to qualify as truly tropical. Even though we never stop trying, so many of the world’s most beautiful tropical trees simply do not do well here. Every so often, however, a new tree comes along that defies all apprehensions and becomes an unexpected superstar. Such is the “Cinderella story” of the gold medallion tree (Cassia leptophylla), which is fast becoming a popular street tree in Southern California.

Tropical-Looking

Native to southeastern Brazil, gold medallion tree looks far too tropical to ever succeed in California; yet it does, and in spectacular fashion. A member of the pea family (Fabaceae), it does have some famous tropical relatives, most notably golden shower (Cassia fistula) and rainbow shower (Cassia xnealiae)—trees familiar to gardeners in Hawaii and South Florida but generally unhappy here. Although it shares the large, showy flowers and tropical-looking foliage of its cousins, gold medallion tree is much hardier to frost, dry heat, and drought than the other two—and that’s what makes it special in California.

Gold medallion tree was nearly unknown here just a generation ago. I first saw one thirty years ago at Rare Plants From Far Horizons, the La Canada nursery and garden of Dr Samuel Ayres Jr, who was instrumental in the establishment of the Los Angeles County Arboretum in Arcadia. Then around twenty feet tall and a little wider, Dr Ayres’s tree was spectacular in full summer bloom, simply covered with huge clusters of yellow flowers. Needless to say, I was impressed, so impressed that I started growing it immediately and eventually put Cassia leptophylla on the cover of a book I would write. Gold medallion tree was one of several Brazilian trees that were featured in the ambitious Los Angeles County Arboretum plant introduction programs of the 1960s and 1970s, and it grew to become one of their most famous tree introductions, especially when it became clear how tolerant of adversity the tree really was.

Spectacular Flowers

Gold medallion tree grows at a moderate to fast rate to twenty to twenty-five feet tall and up to thirty feet wide, growing most rapidly in warm-summer areas. It is essentially evergreen, but may lose some leaves in winter and early spring if exposed to frost or prolonged cool temperatures. As trees mature, they develop a characteristic dark brown furrowed bark, a wide-spreading form, and a dense foliage of long, dark green compound leaves. Each leaf is composed of nine to fourteen, two- to three-inch-long, elliptical leaflets; the pointed tips of the leaflets can be an identification aid when compared to the more rounded leaflets of many other species of Cassia and some of the more tree-like species of Senna. Flowering is spectacular in summer, with basketball- sized, terminal flower clusters covering the tree. Each cluster produces thirty to fifty, fragrant, bright yellow, three-inch-wide flowers over a long blooming period; the show is even more spectacular as the weather heats up. Flowering is followed by conspicuous, foot-long, dark brown seedpods containing many small flat seeds.

Flowers of gold medallion tree (Cassia leptophylla)

Tolerant of Extremes

Successful in both coastal and inland climates of Southern California, gold medallion tree is also recommended for Sunset zones 15 and 16, which extends its possibilities well into Northern California; a particularly fine specimen can be seen at The Ruth Bancroft Garden in Walnut Creek. It does best in full sun and will tolerate a wide variety of soils as long as drainage is good. This tree loves heat, but does not need high humidity to thrive and is actually quite drought-tolerant. It will also tolerate occasional cold temperatures down to 25° F or lower; this was confirmed when even small trees survived the severe 1990-91 freeze in Los Angeles. Gardeners in frostprone areas should note that, like many tropical trees, gold medallion tree will tolerate colder winter temperatures in places that get the warmest summer temperatures. Propagation of this tree is fast and easy from seed, which conveniently produces a nicely uniform crop; we are beginning to notice some exceptionally showy individuals, however, so propagation by grafting the finest seedlings may prove to be a worthwhile endeavor.

The luxuriant, wide-spreading growth habit of gold medallion tree makes it well-suited as a background tree in the garden, but it may also be pruned up to make a showy lawn tree. In Southern California, it is often seen trained to a single trunk and pruned up as a street tree, where it has all the qualities of manageable size and toughness that city and commercial landscapes demand, but with far showier flowers than most such trees. Thus, from a few specimens a generation ago, this Brazilian has now become a true arboreal ambassador, exposing even plant-unconscious Southern Californians to the stunning beauty of tropical flowers as they speed along city streets or look for a parking space at their local shopping center. A real Cinderella story, to be sure!

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