Trees are an important feature of any garden or landscape. They can be a focal point of shape or color as well as a source of shade. Some trees produce nuts or fruit while others are simply ornamental. And trees do a great job of helping clean toxins from our air. Whatever your reason is for planting a tree, here are some tips to help you give your tree its best chance of thriving for years to come.

The first tip is to choose the right tree for your area and climate. To do this well, you need to understand a little about zones. A hardiness zone chart gives you the lowest temperatures a plant can handle. The American Horticultural Society created a Heat Zone map based on the number of days with temperatures over 86 degrees. Lastly, the Sunset climate zone takes into account the whole climate of an area: elevation, length of the growing season, typical rainfall, frost dates, and so forth. For more information on zones go to:https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1022.pdf

If you live in a low desert area like Yuma you need to choose a tree that is suited for the hot, dry summers of heat zone 11. You may have loved the heady fragrance of your grandmother’s lilac tree in Michigan, but lilac is not going to survive in the desert southwest. Most lilac varieties need cold winter temperatures and do best in zones hardiness zones 5-7. And while a few varieties have been developed that will grow in zone 9, none of these will survive Yuma’s heat zone.

Similarly, a tree with high water needs such as a Weeping Willow or a River Birch isn’t going to do well in our area where we get less than 4 inches of rain in an average year. A few tree species that thrive in our area include Emory Oak, Desert Willow, several varieties of  Acacia, Honey Mesquite, Ironwood, Palo Verde, and Royal Poinciana.  This is not a full list; check with your local nursery or search online for other tree varieties that do well in heat zone 11.

Another consideration is the expected size of your mature tree. Honey Mesquites grow to about 30 feet tall (about the height of a 3-story building) and the canopy, or spread, of the tree’s branches, is typically 40 feet wide. A Poinciana is even larger. They can reach up to 40 feet tall and have a spread of 40 to 60 feet wide. That’s the length of a semi-truck and trailer! You wouldn’t want to plant either of these in a small yard or where your tree’s canopy spread would encroach on your neighbor’s yard. And, of course, you wouldn’t plant a tree where its branches could touch power lines.

Another large tree is the Ghost Gum Tree. It can grow up to 40 feet tall and 25 feet wide. This specimen can be seen at the Robert J Moody Demonstration Garden in Yuma, AZ.

If you are planting a tree near your house, be sure you are planting it with the canopy of the mature tree in mind. For example, if the canopy of your mature tree is estimated to be 30 feet, then you want to be sure you plant at least 20 feet from your house. (Half the canopy width, plus an extra 5 feet.) This ensures that the branches won’t come up against your home.

The second tip is to plant the right size tree at the right time of year. Fall and Spring are the best times to plant most trees here. These seasons are fairly temperate with few extreme highs or lows, so your tree has the best opportunity to settle into its new home.

Plant small trees for better acclimation.

Many new gardeners make the error of choosing the largest tree they can afford. But the bigger the tree, the more stress it experiences when transplanted. Although it may seem counterintuitive, experts say that a 5-gallon tree will catch up—and often pass—a 20-gallon tree within three years. Most transplanted trees show little to no growth in the first year after planting. This is because the tree’s growth is primarily taking place under the ground. Trees take up nourishment through their roots. In its first year, a tree is not only growing its fibrous tap roots, or anchor roots, it is also growing fine roots. These fine roots help the tree take up nutrients in the soil as well as moisture and it takes time for them to start growing.

The more shock a tree experiences when transplanted, the longer it will take to settle in and develop a strong root system. And this has to happen for the tree to be ready to expend energy in height growth. Because smaller trees experience less shock, they recover faster. In the second year after being transplanted, some growth in height is seen in most healthy trees, and by the third year, a well-established tree will show a jump in height.

Larger trees won’t show the same amount of growth in height because they are still putting their growth into the root system. Also, a large tree can take more than a year to fully recover from transplant shock.

The third tip has to do with digging the hole for your new tree. Recent studies have shown that the old advice of digging a deep hole and then backfilling with amended soil is not the best way to go. Your newly planted tree may look good for a couple of years but then will often start dying.

Don’t dig too deep of a hole.

Instead, dig your hole only to the depth of the root ball. The roots of the tree should sit on undisturbed soil and the flange of the tree should be even with the surrounding soil outside the hole. The problem with digging deeper than the root ball is that the softened dirt can settle after a few waterings. This will cause the flange of the tree to sink below the surface of the surrounding soil. Water will run into the low area and sit at the base of the trunk which can lead to root rot. If your soil doesn’t drain well, experts recommend planting the tree about an inch above the hole. This allows oxygen to reach the uppermost roots.

Do dig the hole wider than the root ball. A good rule of thumb is to dig out two to three times the width of the pot in all directions. Save the soil you removed. Once you’ve established that the flange (the spot where the roots branch out from the trunk) is even or just slightly above the surface of the hole, use the same soil you removed to refill your hole. Fill the hole about halfway and then pack it down, making sure your tree trunk remains straight. Then finish packing in the remaining soil. Water the tree in the well.

Earlier, I mentioned not to amend the soil. Mixing amendments into the soil was thought to make it easier for the young roots of a tree to spread. What experts found, however, is that the roots then want to stay in this softer soil and don’t reach out into the native soil. The result can be girdled roots or a narrow root system that isn’t capable of properly anchoring the growing tree. Filling the hole with native soil encourages the roots of your tree to spread as they need to do.

The fourth tip is to avoid over-watering your tree. Too much water will push out the oxygen in the soil. Letting the soil dry out between waterings encourages root growth by allowing oxygen back into the soil.

Of course, the roots of a newly planted tree need to be kept moist at first. Water a transplanted tree lightly every day for about 4 to 5 days. Don’t drown your tree. Avoid watering closer than an inch to the trunk, but be sure you’re watering the surrounding soil on all sides of the tree. After the fourth or fifth day, start watering only every second or third day for about three or four weeks. After this time, you only need to water once every 7 to 10 days in dry weather, gradually working up to once every two weeks.

That’s it. Four simple tips to help you plant a tree that will thrive for many years.

Family enjoying the shade of a tree.