August is too hot for any major effort in the garden. It's difficult enough just to keep things watered. You can, however, begin to plan for cooler weather, and you can even start a few select plants. We suggest two summer-flowering shrubs that often make their appearance at nurseries at this time and several shrubs that you can order now for fall planting. In anticipation of the fall planting season, you should start seeds of perennials, annuals and vegetables that will bloom in the spring. And now is the time to plant any fall-flowering bulbs that you might want to try.
As summer gets hotter and other plants begin to pack it in, two shrubs that love summer's heat come into their own. One is the princess flower, Tibouchina urvilleana , a Brazilian shrub that flowers all summer and well into fall. In winter and spring, exhausted from six months of flowering and shivering in the cold, it often appears to be on the verge of death. Leaves are yellowish and sparse; dead flower spikes are everywhere. In April or May, these old spikes should have been pruned off and leggy branches cut back, because as soon as the weather warms every June and July, the princess flower begins growing furiously, and flowers are not far behind. Pinch back young plants several times before then to encourage bushy growth and more flowering branches. That's also a good time to prune older shrubs that have grown too large, or they will resprout rapidly.
The princess flower grows to about 10 or 12 feet. Flowers are large, up to three inches across, on spikes that keep producing new flowers until winter. The tips of stems, buds and even the edges of the leaves are a purplish red that harmonizes with the brilliant royal purple of the flowers. Fallen petals remain purple on the ground and make a pretty leaf litter until they drift away.
Early August is a fine time to plant if you water assiduously. Princess flowers like a rich soil with good drainage, so add amendments. Fertilize in early fall, then again in June of the following year. Since they will not stand much frost, they are grown mostly in the Los Angeles Basin, Orange County, San Diego and in the hills surrounding the San Gabriel Valley. They are not for inland valley floors.
The marmalade bush, Streptostolen jamesonii , can be grown in just about the same areas, though it may need a little more protection from cold weather. Always give it the warmest place in the garden.
This bush is harder to find at nurseries, although, since it flowers in summer and fall, it is most readily available at this time of year. This sprawling shrub is a little unruly for tidy gardeners and is often described as "viny" since the long branches arch out from the plant. Expect it to grow about 6 to 10 feet tall and, in time, to cover 10 to 15 feet of garden. It, too, often sulks throughout the winter, but in spring its growth is rampant, and it can double in size in a few weeks. If frost should nip it back, cut out the deadwood in late April and watch the plant rebound.
Flowers of brilliant orange and gold come at the ends of new growth, so pinching back branches in April and May will make for more flowers in summer. This bush thrives in rich, well-drained soil with ample moisture. Fertilize in spring and again in midsummer.
For a shocking summer color scheme, plant the marmalade bush and princess flower together. The sprawling growth of marmalade bush compliments the more regimented, tree-like growth of the princess flower. When they flower together, wow!