Anything planted near hot wall should be heat tolerant

Q: After reading a recent RJ gardening piece, I have decided to take your advice and replace the bougainvillea and the western redbud with a cat’s claw vine and an apricot tree and protect them with shade cloth. Is it better to plant a bare root fruit tree or a potted one? Also, in this hot spot would a peach have as much chance as an apricot? As to shading the plants and the wall, should they be covered completely or built to only provide afternoon shade? My last question has to do with western redbud. I want to attempt to transplant it to a more favorable location. Is now a good time to transplant and are there steps I can take to help it survive?

A: I don’t remember the “hot spot” you’re talking about, but I am guessing it’s either a west- or south-facing wall and a side facing the same direction. Apricot and peach handle the heat about the same. But peach gets borers much more readily than apricot.

Either one needs to be at least 5 feet from a hot wall. Pomegranate handles heat from a hot wall better than either apricot or peach. Anything you plant there should be heat tolerant.

Bare root fruit trees are usually better to plant than potted, container trees. That is because the potted container trees are left too long in the container. They are too big, and the roots start to circle inside the containers. If you buy a fruit tree that is smaller but in good health and well-branched, there is little difference between the two.

I am a little perplexed because bougainvillea handles heat but does not handle winter cold. Catclaw vine handles both summer heat and winter cold but needs some relief when it clings to a hot wall. A wall facing south or west will get about 160 to 170 degrees in the summer — too hot for any plant including cactuses.

It will need some shade on that wall during the summer months to climb it. Once any heat-tolerant vine climbs the wall, then the area is cooler for planting fruit trees. Both vines use about the same amount of water when they are growing and about the same size

Move the western redbud now until about March if it is less than 3 years old. Make sure the soil is amended and it is firmly staked. Prune about ⅓ out of the tree to compensate for root losses during the move.

Q: Now I am really confused. How would you prune a grapevine that was grown on a patio cover? How can I get larger berries on the vine?

A: Good question. Grapes require a lot of visits. I would avoid pruning grapes from December through about mid-February in our climate unless it’s just to clean them up a bit. The vines will be a tangled mess.

I would cut out or remove whatever it takes to make it easier to see where the fruit is produced. Try to avoid removing the smaller, different-colored wood because that is probably last year’s growth and where the fruit will be produced.

Later these smaller, different-colored parts of the vine will be pruned into a spur or cane the first week of March. The vines will “bleed” from pruning cuts made in late February or early March and before the new leaves come out, but don’t worry about it because it’s not harmful.

Next, determine how much new growth is left. It is oftentimes a different color or texture so it might be easy to see. Ideally, this new growth is in lots of places giving you lots of choices. After you finish your final pruning, then you are done for about six to eight weeks. About two months later is pruning and pinching the immature grape bunches as they are enlarging. That’s in about April or May.

In about May, the berries in the bunches will start to form. You will do two things to get larger berries: Remove bunches so they are about 8 to 10 inches apart and pinch or cut the bottom ⅓ of the developing bunch. I use scissors to do that.

Removing smaller bunches and pinching the remaining bunches thins the berries so those that remain get bigger. Do it early when the berries are the size of baby peas.

Q: Last year I wrote about my dwarf oleanders planted over my pool equipment pipes. I removed those and placed planter boxes with green euonymus in them. These planter boxes face south and are exposed to full sun and can get very hot. They are also exposed to gales of wind coming off the mountain and the dirt gets blown. I am cautious about using rock as I suspect that rock will not allow the heat to escape in the summer. Do you have any other suggestion?

A: I am concerned about growing green euonymus in a hot location. These plants are not trustworthy to grow in hot locations. Watch them very closely for leaf scorch as the summer gets hotter. You may need to get them replaced.

By the way, common euonymus gets about 8 feet tall, and common oleander will get about 15 feet tall. Both of their roots are 18 to 24 inches deep.

I would suggest smaller plants that are shallow-rooted and heat tolerant such as some of the desert sage or desert penstemons. In a place that is hot, you are better off with something from the desert.

If they are grown on top of pipes, then I think you should put something that is smaller and closer to 12-inch-deep roots. That’s why I suggested those.

A mixture of large and smaller rock act like the desert surface. It has a lower surface temperature than asphalt or concrete because of air pockets. I would not be afraid of larger and smaller rock used in a mixture similar to the desert. As close as the texture is to the desert floor, the desert plants will do fine.

Q: When planting new shrubs or relocating plants, I apply a local nursery’s plant tonic. Can fish fertilizer be used as a supplement along with a nursery’s plant tonic or with normal regular spring and fall season fertilizer applications?

A: I looked up this nursery’s plant tonic because I don’t know anything about it. I have never used plant tonics in general. They developed and sold it to compete with a commercial product already on the market.

There is nothing wrong with fish fertilizer and adding it simultaneously as the plant tonic. They will not interfere with each other. Just go slow. The only thing I worry about are over-fertilizing applications. Add ½ of the bottle at first and work your way up. If you see improvements, continue with what you are doing.

Fertilizer applications are OK if the soil has been improved with amendments such as compost. Our soils are extremely low in organic material, and compost is the most effective way of rebuilding this organic matter in the soil.

If you don’t do this, the use of fertilizers, fish emulsion and plant tonics won’t help in the long run. They do not substitute for soil improvement.

Q: I am having a hard time finding compost to use. Will the Black Gold peat moss that a local nursery sells work like compost?

A: Peat moss and compost are two different things. Peat moss is harvested from peat bogs, and it is not decomposed. It is used in soils to help keep them loose and porous and improve water drainage. They don’t provide much nutrition and slowly break down in the soil, faster than coconut coir but much slower than compost.

Compost and peat moss are added to soils for similar reasons, but the addition of compost adds a lot more nutrients to the soil than peat moss. If enough is used, it can substitute for a slow-release fertilizer.

If you add peat moss to the soil, it improves its structure, but you still need to add fertilizer to the peat moss. If you add compost to soil, it also improves its structure as well as adds fertilizer or nutrients to the soil.

In my opinion, compost is much more valuable to add to our soils than peat moss unless you are making a very specialized soil blend like for potting soil or houseplants. If you are growing vegetables, fruit trees, landscape plants, lawns, then compost is a much better choice than peat moss and more cost-effective.

Bob Morris is a horticulture expert and professor emeritus of the University of Nevada, Las Vegas. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.