Free tree expert’s visit open to public

If you are interested in fruit trees and hearing from true experts on the subject, I invite you to come out to the University of Nevada Cooperative Extension Master Gardeners Orchard in North Las Vegas at 2 p.m. Feb. 16 to hear Tom Spellman from Dave Wilson Nursery. He will conduct a tour of the orchard and talk about new fruit tree introductions from Zaiger Genetics. There is no fee. This only happens once a year and this is the first time I have offered the opportunity to him hear to the public.

Q: I'm gardening in raised beds that are 4 feet by 8 feet. I'm not sure how much asparagus to plant. My wife and I are the only ones who would eat it, and I'm guessing we would harvest one time per week during the period they can be harvested. How much of my garden would need to be dedicated for that production level?

A: If asparagus is planted correctly, it should start producing in February and you will stop picking about eight weeks later. When asparagus is in production and when it is warm outside, you will be picking as frequently as every other day to stay ahead of it. If you don't, much of it will be unusable. There is no such thing as picking weekly with asparagus once it is in production.

It does freeze well, it makes great soup and can be grilled nicely. I would say half a dozen crowns should be plenty for you and your wife. My asparagus class will be offered in March at Plant World and through Eventbrite.com.

Q: Our backyard block wall has some white stains on it. These appear where the sprinkler water hits the wall and I want to remove them. I have read online to use things like diluted muriatic acid, but I don't want to kill the plants my wife has throughout her garden. How can I clean the stains, and can I treat the walls to protect from more stains forming?

A: These are salts remaining from either those sprinklers or water from the soil wicking up the wall. Salt dissolves readily in water and when the water evaporates from the wall, it leaves the salt behind. These are probably the salt deposits you're seeing on the wall. Even drip irrigation can cause problems like this since the water can wick through and into porous surfaces.

Our soils, as well as our water, contain quite a bit of salt. Water coming from Lake Mead carries about 1 ton of salt for every 326,000 gallons. It sounds fairly diluted but it is not. The salt in our soils varies much more and can be removed by leaching. The salt in the water, of course, is consistent. The combination of the two can mean some pretty high salt levels.

You don't have to use muriatic acid, but you can use an acid, even vinegar, to help remove it. The major concern with plants is having the acid fall on the foliage. This will damage the plant.

The best way to prevent it is to not use overhead irrigation. In the case of drip irrigation, put the emitters on the opposite side of the plant from the wall, not next to the wall. Perhaps there is a treatment to the wall that could prevent this from happening. I don't know of any.

Q: Your Twitter feed mentioned a good deal on peach trees, which we are going to now purchase. Which two peach trees should we get for a 10-foot-by-10-foot space? I'd like to keep the harvest staggered so we can enjoy the fruit longer. I also have a 5-gallon Bonanza dwarf peach in a whiskey barrel that I started last October.

A: Groworganic.com is offering a special deal on 10 fruit trees for $199, plus $35 shipping. Of the peaches it had available, I would recommend that you look at Red Haven (yellow acidic), Babcock (white subacid) or Stark's Saturn (donut, white, subacid, but birds like it a lot). For an earlier peach, mid-July or so, try Indian Free ( beautiful flesh turning nearly blood red and subacid); try O'Henry ( yellow, favorite at roadside stands and farmers markets) for a later peach.

It is hard to recommend just one or two peaches since they can be so different from each other. There is not really a June peach in the group that I know well enough to recommend.

Q: With this unusually mild Las Vegas winter, when is the best time to transplant dwarf grapefruit trees?

A: By transplant I take it to mean you are moving a grapefruit from one location to another location. Planting or transplanting can be done now. You will have more success if the tree has not been in the ground more than three years. You will have even more success if the tree has been watered by drip irrigation in a fairly small basin or area next to the tree. You will have even more success if the tree was root pruned last fall around mid- to late September.

Root pruning just means you went around the entire tree with a shovel and severed the roots in the approximate location where you are planning to dig to transport it.

Given all that, prepare your hole for planting first before you move the tree. Dig deep enough to accommodate the root ball but not much deeper. It is more important to dig your hole wide than it is to dig it deep. Get your soil amended and add some phosphorus to the soil. Move your tree as quickly as possible to its new location and try to orient it in a similar position, north to south, as it was in the old location.

Backfill around the tree. During planting, run a hose in the hole at the same time you backfill to remove air pockets. Drive a stake next to the tree and into the bottom of the hole into solid ground. If tied to the tree tightly, this stake will immobilize the roots.

I usually use rebar pounded into the soil next to the tree after it has been planted. I wrap the tree and rebar together with green nursery tape to immobilize the roots. This allows the top to move in the wind.

The tree should be planted at the same depth as it was when it was removed from the soil -- no deeper and no shallower. If you have rabbits, protect it with 1-inch chicken wire after planting. Mulch the soil around the tree with wood mulch, keeping it a foot away from the trunk. After one season of growth, remove the stake.

Q: I planted 10 bareroot trees I picked up at the orchard yesterday. I followed the directions from your blog and everything went really well. I cut them all off at approximately knee height but when I got to the apple, I wasn't quite sure what to do. Should I cut off any side branches? Leave desirable ones? Cut them partially back? Or just leave them alone? I am planting my trees in hedgerows 10 feet apart with 4 feet between trees.

A: When planting in hedgerows, make sure the trees are on very dwarfing rootstocks. M111 rootstock is probably not aggressive enough for planting that close.

If any of the branches can be bent down and touch the ground, they should be removed to the trunk. The lowest branches are probably going to be somewhere around 18 inches to 2 feet off of the ground.

On apples look for a whorl of branches, a minimum of four and probably a maximum of six, to leave attached to the trunk. These will be your scaffold limbs, which are limbs that support other limbs which bear the fruit.

Otherwise, if this is to be a hedgerow, you can wire the limbs to a trellis to support them so they don't touch the ground and you could keep limbs as close to a foot off of the ground if you wanted to.

If you are not sure what to do even after reading this, just remove the ones that you know are too close to the ground and leave the rest. Come to the orchard so we can talk, and address the problem next year.

Bob Morris is a horticulture expert living in Las Vegas. Visit his blog at xtremehorticulture.blogspot.com.