A giant spreading shade tree is an incredible asset to any landscape. Shade trees provide a cooler outdoor setting to gather, play or relax. They shade our homes reducing cooling costs. They add several hundred to a thousand dollars or more to the resale value of our property. They may even provide a spot for a swing, hammock or treehouse.
Perhaps you have moved into a new subdivision where there are no trees, or maybe just a few broomstick-sized new transplants set out “cookie cutter” style down the block. Maybe you just lost an old tree and want to replace it. If your home was one of the many new developments of the 1970s (give or take a few years) that came complete with the standard issue Arizona ash in the front yard, you are probably getting to replace it or what is left of it about now.
Whatever your situation, if you are planting a new shade tree you most likely can agree with the statement, “I want shade, and I want it ASAP.” This article is about getting you that shade as soon as we can.
Long Lived, Well Adapted
This article is not about selecting the right species, or listing choices for various areas of the state. That was covered in a previous issue of TEXAS GARDENER. But I can’t talk about growing a great shade tree without at least mentioning that if you don’t start with a long lived, well adapted species you are, well, barking up the wrong tree.
I am often asked, “What is a good, fast growing shade tree?” That is the wrong question. The right question is, “What are the best shade trees for this area, and how can I make them grow to a good size the fastest?”
We should take a moment to discuss planting too. Proper planting is critical if you want a tree to survive and to perform well during the first few critical years. Choose a good location where it has room to grow. Don’t amend the soil in the planting hole. That only creates a large underground flower pot from which roots may be reluctant to venture out into the surrounding soil. It also can form an underground bathtub during rainy spells that waterlogs roots, which can be deadly.
If you are planting a container grown tree, check to see if there are any roots encircling the container. These should be either cut or unwrapped and laid outward in a hole dug to fit them. Circling roots can become girdling roots 8 to 12 years down the line as the trunk and roots grow larger.
Set the tree at the same depth it grew in the container or field from which it was dug. Firm the soil around the roots and water the soil well to remove air pockets. Don’t put fertilizer in the planting hole, especially dry, synthetic salt based products. These can burn tender roots. Wait a few weeks after the tree is planted to begin fertilizing. We’ll say more about this later.
To Stake or Not To Stake
Staking is seldom needed when planting a tree. If a tree is planted right it can hold itself up just fine. Too often when people stake a tree they don’t maintain the setup and the wires end up cutting into the tree. Tree trunks and branches grow stronger with the stresses of movement and it is actually better for the tree to not be tied up to a post where it cannot move at all. When rigidly tied to a certain point that will not move a strong wind could cause the trunk to break at that point.
If you do feel a need to tie something to a stake, stake and tie the two-bit weekend arborist that recommended that you stake your trees, and leave the trees alone. Seriously, there are times when staking may be helpful, such as with a poorly grown, lanky tree with a thin trunk, or in an area with very strong winds.
If you do choose to stake a tree, make sure to use a section of water hose over the wire to prevent damage to the tree. Either place two metal posts on opposite sides of the tree to hold the wires or angle the guy wires down to stakes in the ground in 3 directions. Leave the wires a little loose to allow some movement. Check the wires periodically to see if they need adjusting. By the end of one growing season the stakes and wires should be removed.
No Weeds Allowed
If you want your new tree to take off and really grow, eliminate all competition. In fact I propose a new Texas law. Every tree sold should be sold with two bags of mulch. (I figure if they buy it they’ll probably use it.) Every new tree should have a mulched area extending a few feet out in all directions.
This will deter weeds which really compete with the tree for water and nutrients. By weeds I also mean the turfgrass that all too often is allowed to grow up against the tree trunk. This invites disaster. The lawnmower and string trimmer are notorious ravagers of young trees. I know, I’ve tried to get “just a little closer” with those things only to damage the bark leading to dieback, canker infections or simple loss of the important plumbing pipeline that moves moisture and nutrients up and down the tree.
Mulching along with a little weed pulling can keep the equipment away and protect a new tree’s tender trunk. There are also tree trunk wraps for this purpose but there should not be any need for a wrap if you mulch, and wraps have several problems too. Don’t wrap, mulch.
Apply mulch a few inches thick and replenish it periodically as it decomposes. Don’t pile mulch or soil up against the trunk. This holds moisture up against the lower trunk which is not designed to be kept wet. These “mulch volcanoes” are not good for the tree and can lead to rots near the base of the trunk. Besides, they look silly.
When turf or weeds are allowed to grow under the tree they have a dramatic negative effect on the tree’s rate of growth. Trees are made for a forest floor where leaves cover the surface, not for a meadow where grass roots suck up every bit of water and nutrient they can as they compete with the tree’s roots.
I have seen pecan orchards where some trees were planted in bare soil and others in a Bermudagrass that was kept mowed. A few years down the line the difference was dramatic. The trees with no competition were more than twice the size of those with grass and weeds around them. If you want fast shade keep the mulch out at least as far as the young tree’s branchspread and preferably a little farther the first few years of a tree’s life. Make it think it is at home in the forest with compost and leaves all around it on the soil surface.
Water – The Key to Success
Nothing can match proper watering when it comes to helping a new tree survive its first stressful summer season or making a tree really take off and grow. Too much water drives oxygen from the soil leaving roots in a world of danger. If soggy conditions continue, roots will start to die and root rots may move in to finish the job. Few trees can take such waterlogged conditions.
On the other hand, the more common problem is a lack of water. A new bare root tree goes through a critical time early on when it must get some fine feeder roots established or it will die. Dry conditions or anaerobic soggy conditions during this time are a recipe for quick death.
Container grown trees also go through a critical period in which their new roots are starting to venture out into the surrounding soil. Until they do and start to establish a more extensive root system, a newly planted tree has a root zone pretty much the equivalent of what it was in the container.
When it was growing in the container a nursery employee, or irrigation system, watered it every day to keep the roots moist and the tree vigorous. Now in the ground that same cylinder of roots needs frequent care. The soil around the tree may be adequately moist but the root ball could have pumped most of its available moisture out leaving the tree in need of more water.
I will occasionally dig down a few inches below the surface and feel the soil. You can tell if it is getting a bit dry or if it is still quite moist. Soils differ in their water holding capacity. With changes in temperature, wind and amount of sunshine the quantity and frequency of watering required may vary. That’s why an occasional hand check of soil moisture may be helpful in deciding when and how much to water. We always recommend deep, infrequent watering to develop an extensive root system. But there is a transition period where we must help them go from the daily drink of water for the confined root system to an infrequent soaking to help a well-established tree’s extensive root system through an extended drought.
The first summer after planting is a critical one. It is a bit of a touch-and-go effort to avoid keeping the soil too saturated or allowing the root zone to become too dry. If you can focus watering on the area beneath and maybe just beyond the branch spread, that area where mulch is also most important, you will be on the right track.
When you water the soil surface it can be deceptive just how deep the water penetrates the soil. It may run off of the surface but only have wet the soil an inch or so deep. Build a raised circular berm of soil about 4 inches high and 3 to 4 feet in diameter around a newly planted tree. This berm will serve as a reservoir to hold water until it soaks in. Put about 5 gallons of water into the bermed area and your tree will get a good, thorough soaking.
I have also devised watering devices for trees out away from the home where hauling water is a chore not to be done any more often than is necessary. Take a 5 gallon bucket and drill a few small holes through the bottom. Then toss a brick or rock in it for weight and set it right up against the trunk of a newly planted tree. Fill the bucket with water and you can walk away to do the same for other trees. The water will slowly leak out, thoroughly wetting the soil around the new tree.
After few months the area to be watered should be expanded outward if you want maximum results, but this initial effort will save many trees that would otherwise have been lost during the first warm season. Those same trees will not only survive but will be way ahead of their inadequately watered counterparts when it comes to winning the race to be able to hold a hammock!
Give ‘Em A Boost
Fertilizer is right behind water on the list of things that speed up the arrival of great shade. A newly planted bare root tree needs time to get some roots going before it can use any fertilizer. The soil has adequate nutrition to keep it going for a while. Container grown trees usually have some slow release fertilizer still in the original root zone so they too are in no need of an immediate fix.
After a few weeks, begin to fertilize lightly. Start by sprinkling a couple of tablespoons of turf fertilizer or any high nitrogen product around the new tree. Keep in mind where the roots still are and where they will soon be, so sprinkle it evenly throughout a circular area extending about a foot outward from the trunk in all directions. Water the fertilizer in well. You can also lightly scratch it into the mulched surface prior to watering if you like.
Continue to feed the tree every few weeks with light doses of fertilizer. When the new growth is really taking off, start fertilizing based on trunk diameter. Apply 1 to 2 cups of fertilizer per inch of trunk diameter. I call this the rule of thumb for fertilizing trees since most guys’ thumbs are close to an inch wide, which makes a handy gauge for assessing how much fertilizer is needed.
Repeat this fertilizer application every month from late winter to late summer. Stop by about mid August to prevent pushing too much late season growth, which is more susceptible to cold injury.
As the tree continues to grow through the first 5 to 10 years, keep using the rule of thumb to assess how wide the trunk is about waist or chest high. Each inch gets a cup or two sprinkled in an area as wide as the branchspread. A broom handle sized trunk (about an inch wide) would get 1 to 2 cups of fertilizer. A “Coke can” sized trunk would get about 3 to 6 cups. You get the idea. I should add that if you use an organic product, double the fertilizer to account for the lower concentration of nutrients in the product.
This combination of eliminating weed competition, mulching, maintaining moist soil and pushing them along with light frequent doses of fertilizer will prevent needless loss of a new tree during the first critical summer season or two. It will also turn a slow growing tree species into a medium to fast growing one, and a medium growing species into a rocket.
As the old adage goes, “The best time to plant a tree is 40 years ago. The second best time is today.” Trees are a long term investment. Get the most out of your investment by shifting them into high gear. You may be buying that hammock sooner that you thought!