Bottlebrush can survive with little water

Q: I have a bottlebrush shrub with a dead area. My question is: What would be the best course of action to improve the condition of this shrub? Should I prune out all dead areas, then cut it back?

A: You should determine whether you want it to be a shrub or tree. I like them better as small trees. If you decide to keep it is a tree, then begin your pruning at the soil level so that you have three to five major trunks originating from the soil surface. Remove everything else and keep that area under the tree free from new suckers. Remove any broken or crossed limbs.

They tend to get rather twiggy, so it will require removal of these dead stems and branches as they occur. Remove them at a crotch or where they originate. If this leaves a hole in the canopy, it will grow back eventually, filling in this void. Be patient. They are not terribly fast growers.

Just a few notes on this plant. This is an Australian plant that is not really considered a true desert plant. However, they are typically fairly drought tolerant, which just means they can survive periods of time with little water and recover when water is reapplied to them in sufficient quantities.

They don't particularly like desert soils and have a tough time in our alkaline soil environment. For this reason, they tend to go yellow, which is chlorosis and most likely from a lack of available iron. They also would rather be growing in soils heavily amended in organic material, such as compost, at the time of planting. They also will grow better with wood mulch on the soil surface, not rock mulch.

To correct iron deficiency, apply an iron chelate to the soil in early spring or late winter. The best iron chelate for the job is iron EDDHA (check the ingredients label on the label). You can spray the foliage with an iron solution several times and get a similar result now, but the spring soil application is much more effective and efficient.

You will have to do this every year, particularly if you continue to grow it in bare soil or rock mulch. This plant should be fertilized in January with an all-purpose fertilizer for trees and shrubs.

Q: I planted asparagus crowns in March at a depth of 12 inches. They are in a pit and my plan was to cover the shoots with soil, an inch at a time, as they grew. Well, they grew rather sporadically; I didn't want to inadvertently bury a new shoot so I never backfilled the pit to the level of the surrounding soil. I have about five shoots (out of 12 crowns) that have ferned out. The crowns are about 2 inches underground and about 10 inches below the level of the surrounding soil. Is it OK to backfill the remaining 10 inches at this point? Or would that damage the plants?

A: I would slowly add the soil over time up to the correct level. The problem you have now is that the crowns have adjusted to this soil level, and I would be worried that completely covering the crowns might damage what you have already. When you begin to backfill, mix in plenty of compost with the soil you are using.

Don't just use desert soil. Make sure the soil is loose and can drain easily. Remove any large rocks so that they do not cause the spears to emerge damaged or interfere with their emergence.

Part of the sporadic emergence, I would guess, would have been your watering or how the soil drained. Asparagus loves to grow along stream banks or irrigation canals. It is an oasis plant, so to speak, and loves the same environment as palms, grapes, figs and even pomegranates.

Q: I have planted a garden for the first time this year. Out of three tomato plants, two gave a good yield, the other had blossoms but nothing. The cucumber plants are growing like crazy, and I have a bumper crop of cukes, but now they are turning yellow, and some are deformed. The leaves are turning yellow, and there are hundreds of these tiny little flies all over.

I have sprayed with water but they come right back. The string beans have tons of blooms, but no beans, even though the vines are growing like crazy. Do you think I should tear it all out, and start to get ready for fall planting?

A: I am sending you a copy of Sylvan Witwer's vegetable production book. He was retired from Michigan State University and was a celebrated horticulturist and vegetable scientist who lived in Overton after retirement.

I would read through this and follow his planting guide for the time of year for planting things. It is pretty hot right now for a lot of things to set fruit. Many have trouble setting fruit when temperatures top 95 to 100 F. Your beans are out of season now.

Start ripping out the things that are not producing or producing poorly. Re-amend those spots with compost - good compost. Good composts are expensive. Use a preplant fertilizer at the time of planting that is high in phosphorus and mixed in with the composted soil where you plant. If you are organic, use bone meal or an equivalent high in phosphorus.

Variety selection is important. Record which varieties worked for you and which did not. If you plant at the right time, your beans and cucumber production should be better.

About your crooked cucumbers. Generally, misshapen fruit are the result of stress or poor pollination. Poor pollination results in crooked cucumbers. However, fruit shaped like a lady's figure may be the result of drought during its development or not enough visits by bees.

As temperatures get hotter, bees are less efficient as pollinators. They spend a lot of their time and energy trying to cool down their hives or homes. We have to rely more on our native pollinators like the leafcutter bee.

So poor pollination can cause crooked, misshapen and yellow cukes to form. As temperatures drop and if you keep your plants alive and healthy, you should see your production pick up again. However, replanting cukes from seed also will work and then you get the advantage of having younger, more prolific plants.

As far as your "flies" are concerned, I am not sure what they are or if they are causing problems, but if you feel they are, then frequent applications of insecticidal soap like Safers can reduce pest problems if sprayed directly on the insects. This means spraying under the leaves as well as on top of the plants. Never spray plants when they are in bloom unless it is at dusk or a few minutes after sunrise.

Bob Morris is a horticulture expert living in Las Vegas; he is on special assignment in the Balkh Province, Afghanistan, for the University of California, Davis. Visit his blog at xtremehorticulture.blogspot.com.