Major mistakes when planting will result in tree decline

Beware. Numerous people have complained the planting crews dug the hole only wide enough to fit the box. After that, a little bit of mulch was mixed with the soil, watered in and called good. That’s no deal. The tree will decline and maybe die in a couple of years because of these poor planting techniques.

The major mistakes made when planting are not making the planting hole wide enough, digging the hole extra deep when it’s not needed, planting too deeply and watering the plants too often after planting.

If these deals are too good to pass up, then make sure the planting hole is at least three times the width of the box. Pay planting crews extra to do it the right way if you must. The hole doesn’t have to be dug extra deep, but it should be dug wide.

It’s OK to use the soil taken from the hole for planting, but first mix it with about one-third by volume of compost. If a normal compost is used, make sure to mix in some fertilizer with the soil used for the planting hole. Rich composts don’t need extra fertilizer in the soil mix.

Use this soil mixture for filling the planting hole around the root ball and then water it in generously. Water it like this for two days in a row.

Make sure the tree is watered thoroughly at planting time. To force the water deep in the planting hole, construct a well or moat 4 inches tall just above the planting hole and fill it with water.

The planting holes shouldn’t be super deep. If a hole dug in the soil drains water overnight, there is no drainage problem. However, if the water is still in this hole by morning, then there is a drainage problem and other planting methods are needed. But poor drainage is not frequent in most of our landscapes.

The soil around the tree in the box or container should be milk chocolate in color when wet and the same level as the rest of the landscape soil when everything is finished. The tree should not be below or above the surrounding soil when finished.

Staking trees and shrubs can be very important in getting the roots established during the first year. The stakes that come with 5-gallon and 15-gallon plants are usually good enough to reuse if cut free from the plant and pounded into the solid soil at the bottom of the planting hole so the plant roots can’t move.

The purpose of staking is to keep the plant roots from moving, not necessarily the top of the plant. The top of the plant should be free to move in the wind.

Q: I live in a climate very similar to Las Vegas: USDA Zone 8B. I planted a 1-gallon Texas ranger shrub two weeks ago in sandy/stony soil, watered it with about 2 gallons daily for 10 days. Afterward, I put a 1-inch deep, bark mulch on the soil surface. Now, three weeks later, the leaves are yellow, brittle and crunchy on the lower stems with curling leaves on the top. I think I overwatered, but I’m not sure.

A: Yes, sounds like they were watered too often and now probably root dead. After the initial watering, let the soil drain and give the plant roots air.

The plant roots drowned because the plant was continuously watered. Watering the plant with 2 gallons is about the right amount after planting. It could even be more than that. But after that, schedule the irrigations to skip at least one day so the water drains from the soil and the roots can breathe.

This time of year, probably once or twice a week watering is enough, even for sandy/rocky soil. The soil around the roots was amended so it will hold water. The bark mulch on top of the soil gives you about a day extra between irrigations.

The bad news is that the soil surrounding the overwatered dead roots is probably contaminated with root disease problems. I suggest digging a new hole for planting, at least 2 or 3 feet away from the old, contaminated hole.

Dig the hole 2 to 3 feet in diameter for a 1-gallon plant. It doesn’t have to be deep but wide. Next, mix the soil taken from the hole with about one-third compost.

Wait until the last minute and finally remove the plant from the container. To do this, turn the container over and let the plant slide onto your hand. Lower the plant into the hole, holding it by its root ball, and place it so it’s resting at the bottom of the hole.

As you are pushing this mixed soil back into the planting hole, everything is wet. Make this planting soil a slurry by adding water slowly to the hole with a hose so this slurry flows and fills all the gaps around the root ball. You should see air bubbles surfacing from the slurry.

Build a 2-foot-wide moat around the plant to force excess water down. Fill this moat with water. Do this twice and no more than that.

If the plant came with a nursery stake, push it into the wet, solid soil at the bottom of the hole next to the plant and re-tie the plant to the stake with stretchable, green nursery tape. This immobilizes the plant until the roots have anchored it into the soil. Remove this stake at the end of the growing season.

If you buy 5-gallon plants, use about 5 gallons of water when irrigating with the timer. If you buy 15-gallon plants, plan on about 15 gallons of applied water when irrigating. What killed the plant was watering too often, not the amount applied.

Q: What plants can I plant in my front and backyards? I want plants that grow large enough to produce shade.

A: Shade only what’s needed. This is usually the west and south windows and walls. A single-story home needsonly, at the most, 25-foot-tall trees or shrubs. A two-story home can handle trees to about 35 or 40 feet tall.

Selecting trees taller than needed just looks funny when they are mature. Big trees need big spaces like parks and malls to look good.

Winter low temperatures should be the deciding factor for permanent trees and shrubs important to the design of the landscape.

Then there are plants used for fun. Fun plants can be selected for any low winter temperature, but expect damage or to lose them during cold winters. In the Las Vegas Valley, use a winter temperature of around 20 degrees minimum for the most important trees and shrubs in a landscape.

To see which plants are available, there are three choices: buying from a local nursery or garden center, taking a road trip to buy plants or purchasing plants online. Buying online starts in October with shipments beginning in January for spring planting of winter-hardy plants. Plants bought online won’t have any soil around the roots, so more care at planting time is needed.

To aid your search for the right plant, use two places online: the plant database from the Southern Nevada Water Authority or Arizona State University’s plant database by Dr. Chris Martin.

To access ASU’s plant database, type in the plant’s “common name” followed by “ASU.” To access Southern Nevada Water Authority’s database, start by typing in “SNWA” and “searchable database.” Pick three to five different plants in case the plant you want is not available.

Q: Should I be saving potting soils from seasonal purchase plants? I have been saving soils for years. Should the soil be thrown away at some point?

A: Potting soils can be saved and reused for years. They can be valuable when added to our soils because of the organics they contain. These never go bad. But these organics don’t contain any plant nutrients, and they can harbor diseases if used during their first few months after saving.

Rid this aggregated potting soil of any diseases it might contain by moistening and then placing it inside a clear plastic bag. Place this clear plastic bag full of potting soil in the summer sun for a few days.

When it reaches a temperature of 180 degrees for 30 minutes or more, it will be sanitized of any diseases. Once sanitized, they are ready to reuse.

Bob Morris is a horticulture expert and professor emeritus of UNLV. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.