Roger's Tree Pick for October: Golden Rain Tree

Well, the summer has come to a wrap and cooler days and cooler nights are on the horizon. Yet this transitional period of the year has many wonders to behold in the tree kingdom as well.

While the plants are beginning to start their own process of slowing down and preparing for the variables of winter, the garden is still in a vibrant season and beginning to change some of its color in the foliage, along with the bounty of a year’s growth of assorted fruits, veggies and the beginning of “Indian Summer” with color in the canopy of her foliage.

Early autumn in Southern California has many trees to enjoy and this month I have chosen the lovely Golden Rain Tree (Koelreuteria paniculata). This specie of trees is from the open forests of China, Japan and Korea.

Another Koelreuteria that is very similar and sometimes easily confused is the K.bipinnata, Chinese Flame Tree, from the southwestern area of China. There are three species that are available from various local nurseries: K.paniculata, K.bipinnata and the K.elegans from Taiwan and Fiji.

The genus is named for Gottlieb Koelreuter (1733-1806), a professor of natural history at Karlsruhe, Germany, and an innovative student of plant hybridization for his time.

Koelreuteria takes to most well-drained soils with moderate watering and the tree should be staked well when it is young to assist in forming some good structural branches. It can be used as a patio tree, lawn tree or street tree for it has a deep root system and its roots are noninvasive.

The smaller of these trees is the Golden Rain Tree, which is considered a medium-sized deciduous tree with a dense round crown composed of ascending branches. This tree grows to about 35 feet height.

This is the glorious time of year when its flowering panicles burst into a yellow shower of blossoms on the top of the canopy, but I must note the abundant flowers do also attract a good number of bees for the nectar.

Very shortly after the individual flowers reach their peak, another beautiful stage occurs when the trees go into their seed pod cycle. These delicate pink lantern-like capsules begin creating another unique and ornamental stage for this time of year. Within these capsules exist the pea-like seeds.

Many people like to use these lantern-like pods as decorative branches in floral arrangements and bring a little of nature into their homes.

Koelreuteria paniculata is often planted around temples and gardens in its native land and holds a sacred connotation because its seeds are used in religious rites. The flowers of this species are also used for their medicinal properties and have been one source of yellow dye in China.

This tree is very versatile and can be planted in many types of growing conditions. The Golden Rain Tree can take heat, cold, no irrigation (once established), wind and alkaline soil. I suggest some juvenile pruning when the tree is young to get its gawky shape into control, but once you have established some basic trunk and branch stem structure, it should be fine on its own with just periodic canopy thinning.

So if you are looking for some additional yellow color at this season for your landscape, consider the blossoms of Koelreuteria to give a splash of autumn yellow, golds and pinks in her flowers and seed heads.

Other great yellow flowering trees for the season are the Yellow Oleander (Thevetia peruviana) and Tecoma stans, known as Yellow Bells, Yellow Trumpet Flower and Yellow Elder. This large shrub is also available as a trained standard smaller tree and blooms off and on from June to January. I will present these two “Mellow-Yellow-Fellows” at a later date in my writings of this column.

A few readers have contacted me as to their interest in some of the trees and plants I have presented in past articles and have stated that some of the more unique plants that I have featured have been hard to find. That might be true in some cases, but in my opinion that is part of the fun. If we don’t ask the nurseries for some more unusual plants, we are going to have the “same old, same old” production plants and this can create monoculture gardens in our neighborhoods. How boring!

San Diego County has one of the best growing climates with the world with our wide and varied Mediterranean climate. Enjoy the plant variables that can be incorporated into your garden and by all means have fun with it.

It is up to you, my horticultural friends, to go the extra mile and go on the quest, for every plant and tree I have discussed in my past articles is out there. The adventure of the horticulture trek is part of the quest and the pleasure in the find.

If you need help in securing some of the plants I have written about over the past couple of years, give me a jingle and I’ll find them for you.

Roger Boddaert, also known as the Tree Man of Fallbrook, is a certified International Society of Arboriculture (ISA) Arborist. Roger may be contacted at (760) 728-4297.