Deep soak would help oleanders bloom
Question: We bought a house in Sun City about four years ago. In the backyard, we have some old oleander bushes next to 6-foot-high concrete fences. They have seldom bloomed, only a few dark red blossoms. In February, we had them cut down to about 2 feet and had the old wood cut out. In the beginning of May, we fertilized them. They still only have a couple of blooms on each bush.
Should they be hooked up to our irrigation system? Should we have them cut back again? They are about 4 feet high. What can we do to get them to bloom?
Answer: Oleanders, or Nerium oleander, really don't need to be pruned as much, unless you want them to stay extremely low. This plant is used for hedging and screening, so I don't recommend pruning so severely, if that's what you are trying to accomplish. Oleanders do not need fertilizing; they will do well in almost any soil unless they have contracted oleander blight. I think you need to hook them up to your irrigation system or provide them a deep soak at least once a month during the summer. Watering will create more lush growth and possibly more abundant flowering. You can rely on rainfall in the winter.
Q: We have a very tall eucalyptus tree that the tree trimmers said is about 100 feet tall. We have hired several arborists for their opinions about the tree. One said it was a dying weed that should be cut down immediately. Others said it just needs to be thinned out properly to allow the wind through the upper branches. In the past two years, it has been dropping rather large branches. During the warm/hot months of the year, the bark on the tree sheds, and the mess all over our property is prodigious and very hard to clean up. Do you know why the bark is shedding like this? Could it mean the tree is sick? It is not watered. It is a gorgeous, mature tree (30-plus years old) that provides beautiful shade; it would be heartbreaking to have to cut it down. What do you think?
A: With great eucalyptus comes great responsibility. Many species shed and drop their leaves a lot, especially as a response to extreme heat. Any loss of a nearby water source will affect a large old tree. Deep watering or direct injection of water into the root zone will help it get through the summer. Eucalyptus grow fast and provide shade, but the trade-off is the litter.
Q: There is a grass that grows well in the shade. It is St. Augustine. I live in a townhouse, and the yard was bare because of the shade of the trees. I asked the homeowners association to please get me some St. Augustine, and they refused. So I bought two loads myself and planted it. I was 70 at the time. It looks great still — after nine years. This is the grass my mother had in Texas, and she suggested it for my yard. In my other house, I brought home a shoebox full way back when and got my yards up and running. It doesn't take much water since the roots are close to the surface. Just a thought.
A: St. Augustine is an alternative for the shady lawn, but it comes at a cost. It takes more water and more fertilizer, and it goes dormant in the winter. This grass is popular in the Houston area where rainfall is much greater.
Brian Kissinger is director of horticulture at the Desert Botanical Garden. E-mail your garden questions to bkissinger@dbg.org. Read previous columns at home.azcentral.com.