California sycamore (Platanus racemosa)

I have planted a small sycamore tree that is about 1 foot tall. It is in the sun and doing fine, with new growth on it already. My question to you is: Besides topping the tree, is there some way I can keep it from growing too fast and thin? I’ve looked to buy a sycamore but every one was topped one way or another.
– Tom Walsh, Reseda
The best way to ensure that your young tree does not grow too fast or thin is to do nothing at all. Let nature take its course.
A mistake often made in training trees is to cut back lateral-growing side shoots. These shoots not only stabilize the young tree but send valuable, strengthening carbohydrate into the trunk, and send growth hormone down to the developing root system. When a tree is planted, the priorities are to thicken the trunk and establish the roots. There will be plenty of time for the tree to get taller in years to come.
I was recently at Lake Balboa and noticed two rows of young sycamores just inside the Woodley Avenue entrance, east of the lake. These trees are 8 or 10 feet tall and appear never to have been pruned. There are lateral branches growing out of the trunk from the top of the trees nearly down to the ground. The trees look like large gum drops or small pyramids; in any case, they are perfectly symmetrical, quite healthy, and do not look like they have suffered from lack of pruning.
At most tree farms, there is a rush to get young trees out the door. Every bit of lateral growth is rubbed or snipped off before it can get started. As a result, you buy a 6-foot tree with a skinny trunk that can barely hold itself up, would blow over in a Santa Ana wind or winter storm, and must be staked when planted. Sometimes the tree never develops the ability to stand upright without a stake and must be removed within a few years of planting, or it grows at such a precarious angle that you are never comfortable in its vicinity, even when it has reached maturity. Trees that are allowed to grow wide as well as tall will allow you to sleep peacefully at night no matter how hard the wind blows.
I planted red apple ground cover several years ago, and it is wonderful! However, grass and/or weeds continue to grow in certain places. Is there any herbicide or weed killer that would destroy everything but the red apple? I have tried spot spraying Round Up, but it obliterates everything.
– Dorothy Koetz, Woodland Hills
There is one tried-and-true technique for killing weeds without harming surrounding plants. Don rubber gloves and spray Round Up on a sponge. Brush the sponge on the weeds, taking care not to touch your adjacent plants or ground cover. This should do the trick.
In addition, where succulents such as red apple (Aptenia) are concerned, magnesium chloride has long been recommended for contact weed control. You should be able to find this preparation at any well-stocked nursery. I would spray it experimentally, in a small area, to make sure it does not damage the red apple, before applying it over the entire plot.
Last year, I bought a blooming plumeria. It did well in the pot on my front deck. Early this year when all of the leaves dropped, I planted it under a silk tree. It gets filtered shade throughout most of the day and about one to two hours of less-filtered sun in the afternoon. The plant has leafed out very nicely but has no blooms to date. Can you offer a solution?
– Marshall Maydeck, Arleta
Plumeria is problematic because, while sensitive to frost, it needs more than half a day of sun to bloom. A silk tree (Albizza) provides rather substantial shade, which might be the reason your plumeria has not flowered. However, the fact that you transferred it from a pot into the ground could also explain your lack of blooms. Plants transplanted from pots can take up to several years to adjust to a particular garden spot until they finally are able to flower.
TIP OF THE WEEK: Do not let the heat intimidate you, at least where planting tropical fruit trees such as citrus, mango and papaya, as well as palm trees and cactuses are concerned. All of these plants actually prefer to be planted during the summer.