Trees

Caring for Trees

Fall and winter are the best time to plant trees, since they don't suffer from transplant shock as much as summer planted trees. Trees need the opportunity to grow roots before being subjected to summer heat and dryness. In this section we will attempt to outline the primary maintenance considerations for planting and growing trees.

Fertilizer

During the first growing season, don't fertilize with high nitrogen fertilizer. Use root stimulators (monthly during growing season) or slow release organic fertilizer at half the recommended rate. During the second growing season, fertilize 3-4 times a year using a slow release fertilizer.

Never use a herbicide containing fertilizer anywhere near the tree's root system!

Location and Planting

Plant a tree half its potential spread away from any structure. Do not plant over underground utilities. Dig the bottom of the hole a few inches in diameter larger than the root ball. Dig the depth of the hole the same as the depth of the root ball. Place the tree in the hole so the top of the soil root ball is at least at the soil line or slightly higher. Trees settle after being watered.

Water the plant, water the hole, water the plant in the hole.

"Water the plant, water the hole, water the plant in the hole" is an effective rule of thumb when transplanting. Watering the new plant before removing it from its container helps the soil stick to the roots while ensuring that the root ball is well-irrigated and all the available roots have moisture. Watering your newly dug hole allows you to check for any drainage problems that you might need to correct, ensures that the surrounding soil is moist, and reduces the possibility of water being wicked away from the new plant's root ball into surrounding soil. Watering the plant in the hole after it has been transplanted helps the root ball and surrounding soil to settle and reduces the number of air pockets.

Do not allow the tree to settle lower than the original soil line. Fill the hole with the same soil removed from the hole. If you fill the hole with amended soil, the roots will not want to leave the hole.

Pruning

Selective pruning should be performed after the first growing season. Prune during the December 15 to February 1 time frame. Especially don't prune oaks from February 1 through June 1 due to oak wilt problems. A properly dug and planted tree needs no pruning except to remove broken branches and growth faults (crossing branches and downward growing).

Lower branches should be left on the tree as long as possible. After the first year, no more than 1 whirl of limbs should be removed each year. The use of pruning paints (except on oak trees) is not recommended.

Watering and Mulching

Water the newly planted tree until the hole is soaked. This will saturate the roots. Water, as needed, for at least 18 months by placing a soaker hose around the base of the tree and slowly (several hours) saturate the area. Do not depend on a sprinkler system to do the job. Usually you need to water when the soil has dried to a depth of 4-6 inches. An easy way to test soil wetness is by probing with an 18-inch piece of iron rebar. If the rebar is wet or muddy, do not water. If the probe comes out dry or damp on the end, its time to water. During a hot, dry summer, check the soil every 4-5 days. It is equally important that you do not over-water a native or adapted tree.

Place mulch over the area of disturbed earth, leaving a few bare inches around the trunk. Mulch will help soil retain moisture while also preventing soil compacting by keeping lawnmowers, etc. away from the root area. During the first year, add mulch 3-4 times.

For additional information, refer to the watering and conservation and the mulch sections.

The Proper Tree Care video from the City of Allen's Sustainable Landscape Series addresses proper tree care, including the best varieties, watering and maintenance.

Ten Reasons Trees Die

#10 Tree not adapted to North Central Texas heat.

A native or adapted tree will tolerate North Central Texas' long hot summers, the occasional cold winter and alkaline soil. Trees grown in others parts of the country may not thrive, or even survive, here due to these factors. Non-adapted trees can have a very short life span, problems with insects, diseases and/or leaf drop.

#9 Not adapted to alkaline/clay soil.

#8 Trunk was damaged during transportation/planting.

Be careful about damaging the bark while moving the tree. The vascular system (similar to our own veins and arteries) of a tree is directly under the bark. Since a young tree has thin bark, it is very easily damaged. If the damage is severe the tree will die because it lost its ability to transport water/nutrients from the roots to the stems and leaves.

Avoid damage by transporting it in a manner that keeps the trunk bark from rubbing or hitting any surfaces in the vehicle and by carrying the tree by the container, not the trunk.

#7 The wire used to stake or label the tree was never removed.

Remove all tags from the tree. Keep the tags, with the planting date, for your records. Do not stake a tree unless necessary. Most trees don't require staking unless the tree is located in a windy area. Cover the staking wire that contacts the trunk or limbs with pieces of garden hose or similar material so the wire doesn't cut into the tree. Remove the stakes and wire in 6 months to a year. If left around a tree or limb, a wire can girdle a tree, which cuts off the supply of water and nutrients.

#6 Tree was planted too deeply.

Plant the tree so the root ball sits firmly on the bottom of the hole with the top of the root ball even with the surrounding soil or slightly higher. It is important that you don't plant the tree too deep. Start by digging the hole the same depth as the root ball. Then dig the width of the hole at least twice the width of the root ball. After placing the tree in the hole, fill the void with the original soil (after removing any rocks or debris). Water thoroughly to settle the soil and tree. Cover the exposed earth with 6"- 8" of bark mulch right up to, but not touching, the trunk.

#5 Tree was not healthy when purchased.

Select a healthy tree. Check the tree for any splits in the bark, broken branches, insects and healthy white roots. If it is possible to inspect the roots of a tree before purchase, do not buy the tree if the tree has encircling roots. However, if the tree has been purchased with encircling roots, spread the roots before planting or cut through them. New roots will grow where you cut the circling roots. If left untouched, circling roots could eventually girdle the tree and strangle it.

#4 String trimmer or lawnmower damage to trunks.

A tree trunk hit by a string trimmer and/or lawn mower will lose part of the vascular system. If the tree is hit too often, the tree will die. Keep a thick layer of bark mulch around the tree. This cuts down on evaporation of water from the root zone, moderates the soil temperature, helps control weeds and keeps the trimmer and mower away from the trunk.

#3 Roots over dried while waiting for the hole to be dug.

Keep the tree watered until you plant it. Many a tree has over dried while it waited for the end of football/hockey/basketball season. Place the tree in the landscape where you want to plant it. This will help acclimate it to the light and wind. Most container grown trees need water every day during the heat of the summer.

#2 Leaves dehydrated while being driven down the highway.

Don't transport a tree in the back of a truck, sticking out of a car window or a car trunk without covering the tree. Cover it with a bed sheet or similar cover. If not covered, the wind will dehydrate leaves and small limbs. As a result, the tree may drop its leaves later.

#1 Lack of water or over-watering during the first 18 months.

And the #1 killer of newly planted trees.... is lack of water or over-watering during the first 18 months. It usually takes at least that long for tree roots to become established and help the tree survive hot, dry North Central Texas summers. During this time, use the soil wetness test on a weekly basis to guide your watering schedule. See the watering and mulching section regarding the use of an iron rebar probe to conduct a wetness test.

Leave it on the lawn! Yard clippings can pollute nearby streams and creeks.