This spring, if you can call it that since there still doesn’t seem to be any summer, has been devastating to early fruit production. The early apricots are not as sweet, early peaches have pits that are not hardening and maturing, making freestone-type peaches act like clingstone types. Aphids, sometimes called plant lice, are hanging on a lot longer with this cool weather when their numbers would normally be decimated with the heat and lack of humidity. Just wait. Things will turn around when the heat comes. Enjoy the cool weather while it lasts.
Registration for the next master gardener training classes will take place at 9 a.m. Wednesday at the University of Nevada Cooperative Extension Lifelong Learning Center, 8050 Paradise Road. The fall semester begins Sept. 13 with classes on Mondays, Wednesdays and Fridays from 9 a.m. to noon. For more information on this volunteer program from Cooperative Extension, please call the master gardener help line at 257-5555.
Q: Can you grow a pineapple guava bush in full sun in Las Vegas?
A: Yes, you can but it does like a little bit of relief from the late afternoon sun, if possible. Just do not put it close to a hot wall with reflected heat and light.
Also, improve the soil at planting and use an organic surface mulch.
Pineapple guava has been grown in Las Vegas fairly successfully for many years. It will suffer from yellowing due to lack of iron and possible borer damage so try to keep a healthy canopy for shading lower limbs. Treat it like you would fruit trees and do not plant it in the middle of a desert landscape surrounded by rock mulch and cactus.
The fleshy flowers of pineapple guava, sometimes called guavasteen, are sweet and floral when you eat them and are great in salads. The plant will fruit if you put another variety close by that blooms at the same time.
Q: I’m trying to identify an insect on my grapes. Attached are three photographs from my grape vine. I’m not sure what they are so I didn’t want to spray them just yet. The closest picture I could find on the Internet was that of the grape flea beetle. There are plenty of them.
A: It is grape flea beetle and it can cause damage to the leaves during the spring and sometimes the fall as well.
Damage by the insect is from feeding, which causes holes in the leaves, sometimes extensive. Grape leaves will come back quickly after the insect is gone. The feeding by this insect lasts maybe three weeks and it is over. Unless it starts to look extensive, I would not bother spraying and let the plant recover on its own.
Q: I had planted three, five-year-old flowering dark-leaf plum trees. These trees were planted last fall and are looking healthy. My question is when do I start watering these trees for 2010? Secondly, when do I fertilize them and what should I use?
A: We are watering deeply, twice a week right now at the University of Nevada Cooperative Extension Master Gardeners Orchard in North Las Vegas. A small tree will probably be fine with about 10-12 gallons at each watering.
Our trees are in wood mulch so they can go an extra day without watering. If in rock mulch, you might not make twice a week watering.
It will not do very well without extra care if planted in rock mulch. If it is planted in rock mulch, then it may be all right for a few years (up to about five) and then you may start having problems.
It is not too late to fertilize. If in rock mulch, make sure you add an iron fertilizer to the planting area near the source of water and let the water carry it in. For flowering trees try using a good rose fertilizer.
I don’t want to give you specific numbers because there are so many different fertilizers out there you may never find the exact fertilizer numbers. But the first number should be moderate (8 to 12 or so), the second one high or moderately high (15 to 20) and the last one around the same as the first number. This is generally a 1-2-1 ratio of nitrogen, phosphorus and potassium.
Q: Can we use the slightly soapy water from our dishwasher for our plants?
A: I don’t see a big problem using soapy water for spraying on your plants from the plant’s perspective. Check with local and state agencies to make sure it is not against statutes or ordinances. The state department of environmental protection would have jurisdiction on this.
In saying this, then you should use plant-based detergents rather than petroleum-based products and look for the words certified biodegradable rather than biodegradable unless they tell you how long it takes to biodegrade.
You might also check to see if they contain any artificial dyes or fragrances. Avoid products that have these ingredients added to the product. Otherwise, you should be fine.
Q: You have said several times that it is good to add much mulch around trees that are not native to the desert, like most fruit trees. I have done so but the emitters for our drip irrigation system are still above the mulch. I worry that the drip irrigation will now just water the mulch and not the soil. So should we leave a blank area around the emitters so that the water gets directly to the soil?
A: Emitters should be above the mulch. You want to be able to see them and check them for plugging. I would do this once a month. If you water long enough and deep enough (enough gallons) it will get through the mulch.
Q: I have a question about watering new trees. How much and how often should I water a plum tree and a dwarf orange tree?
A: Much of that depends on your soil so you have to monitor the water in the soil to be sure.
At the orchard we are watering twice a week right now and giving the trees about 1-2 inches of water in the basin or depression below the trees. The basins are about half the size of the tree’s canopy. The smaller trees are getting 2 inches and the larger trees are getting 1 inch of water; 1 inch is not enough water in the smaller basins.
Each watering should penetrate to at least 12 inches deep.
Q: My neighbor’s oleander lifted up his patio slab here in Summerlin. I have three white oleanders growing near a block wall. My thoughts are that the roots would not harm the wall since they could easily go under the wall’s foundation and then continue to run horizontally. Have you heard of oleander roots harming an adjacent block wall?
A: Not really. I have been present when footings under walls have been excavated with oleanders growing next to them for about 20 years and have not noticed that problem.
What I have noticed is that when oleanders are planted next to block walls and they are allowed to grow like multistemmed trees resulting in the limbs resting on the block wall, then the wind movement can knock the blocks down and ruin the wall.
Bob Morris is an associate professor with the University of Nevada Cooperative Extension. Direct gardening questions to the master gardener hot line at 257-5555 or contact Morris by e-mail at firstname.lastname@example.org.