Tree Care Basics

TREE CARE BASICS

Apple Valley Nursery wants you, our customer, to be successful in selecting, planting and caring for your new tree. We understand that purchasing a tree is an investment in the value and aesthetic environment around your home. This Tree Care Basics handout will provide you with helpful information so that your tree will grow successfully and add beauty to your surroundings.

Several tree care areas will be covered in this guide: selection, site preparation and planting, watering, fertilizing, pruning and winter care for your tree.

Selection:

Perhaps the most important aspect for a successful outcome is selecting the right tree for the right site. While it is true that trees do have tolerance ranges, trying to force a desired tree to “fit” into an unsuitable location is only inviting problems. Forcing a tree to grow in an unsuitable site will only cause undue stress on the tree, thereby opening the door for disease and insects. To help you select the right tree for the right site, take time to answer the following questions:

1. What is the tree’s intended purpose? Shade? Privacy? Visual Interest? Specimen? 2. How much space does the location have to offer, both in terms of width and height? Keep in mind the growth needs of surrounding trees and shrubs. 3. Are there any overhead power lines or underground utility lines that you need to avoid? You will need to call your local power/utility company to safely determine where underground utility lines are located. 4. What type of soil does the location have? Does it drain well or is it heavy clay? You may want to have a soil test completed to determine what amendment you need to add to improve the quality of your soil. 5. How much sun (measured in hours) does the area receive? 6. Know what the hardiness zone is of the location. The Minneapolis/St. Paul and surrounding areas are considered to be zone 4 (areas such as Cambridge, Princeton, St. Cloud and further north up to the Canadian boarder are considered zone 3).

Knowing the answers to these questions will help in selecting a suitable tree for your location.

Site Preparation and Planting:

Once you have selected a suitable tree for your location, you can begin preparing the site for planting.

1. Digging the hole: The hole should be twice as wide as the container or root ball. This gives the roots space to spread out and allows the tree to become established more quickly. To determine the depth of the hole it is important to find the root flare on the tree. The root flare is found at the base of the trunk where the roots start to flare out from the trunk. Recent studies from the University of Minnesota indicate that planting a tree too deep or mulching too close to the trunk can encourage Stem Girdling Roots. When planting a tree it is best to gently dig away the soil on top of the container to find the root flare. Once found; plant the tree so that the root flare is even with the soil surface. This will discourage the adventitious roots from growing out and encircling the trunk of the tree. If adventitious roots develop, over time they can eventually choke the tree and cause its death. 2. Soil Amendments: If soil amendments are recommended based on your existing soil type, you will need to take 2/3rds of your original soil and mix it with 1/3rd organic material (soil amendment) to enrich the soil. This organic material could include compost, peat, or composted manure. Peat moss is good for both clay and sandy soils. It will help retain moisture in sandy soil and will help break-up hard clay and improve drainage. 3. Remove the plant from the container. Check the soil ball for any circling roots. If you find roots circling the root ball, use a sharp knife to vertically slice the root ball inch inward in 4 areas (quarters) to break up circling roots and stimulate new outward root growth. If the underside of the root ball is also tightly root bound, cut an “X” across bottom to break up the roots. Next place the tree in the center of the hole keeping the root flare even with the soil line (as described in #1). 4. Backfill the hole: Use the soil mixture (as described in #2). Never backfill a hole with soil amendment only. By backfilling the hole with a mix of original/organic soil, you create an acceptable transition zone for the roots to grow through. After backfilling, gently tamp down the soil so that it is firm around the tree. Water the tree well. 5. Mulch: It is best to keep sod/grass from growing around the trunk of the newly planted tree. Sod/grass competes with trees for moisture and nutrients. Once planted, it is a good practice to use decorative hardwood mulch. Place mulch around the tree (such as pine bark nuggets or cedar mulch) 4 to 6 inches deep. This will help keep the roots cool and prevent the soil from drying out. Remember to keep the mulch 3 inches away from the trunk of the tree.

*A note about tree grafts: Most trees (especially fruit) are grafted onto hardy rootstock. The graft portion of the tree is located at the base of the trunk, usually several inches above the root flare. The graft looks like a bulge or knot in young trees. In time (usually 3-5 years) the trunk of the tree grows around this graft and will not be noticeable. Be sure to distinguish between the root flare and the graft site. The graft site needs to be above the soil line. The root flare should be at the soil line.

Watering:

A key aspect to successful growth and health of any tree is proper watering. As living organisms, trees need oxygen, water and nutrients. In this handout, we will cover the watering needs for trees.

When watering, keep in mind the type of soil that you have as well as the weather patterns. Trees planted in heavier clay soils will need less watering than trees planted in sandy soils. Additionally, during periods of hot dry weather you may need to water more frequently. Once trees are established (healthy and growing well 1 year post planting), they may only need to be supplementary watered in periods of drought.

Newly planted trees need watering on a regular basis, at least once a week. If you receive sufficient rainfall during the week, adjust your watering amount accordingly. It is better to water deeply and less frequently than watering a little bit everyday. As a general rule, newly planted trees need an inch of water per week. When using a sprinkler or soaker hose, some people find it helpful to gauge this by putting an empty tuna fish can out to measure how long they need to water to actually obtain 1 inch. Never automatically water without first checking to see if your tree needs water. If necessary, place your finger in the soil 3 to 4 inches down. If it is dry, it is time to water.

Continue to water your tree as necessary during the growing season. Decrease watering in the early fall then increase watering in late fall until the ground freezes. This is especially true if you have planted evergreens. Evergreens continue to store water in their roots, trunks, branches and needles until the ground freezes. If evergreens go into winter in a drought state, they are more likely to suffer from winter burn.

Fertilizing: Yearly fertilizing promotes the health and growth of trees. Healthy trees are better prepared to ward off effects of disease and insects. Choice of fertilizers and timing of application are frequent questions of customers.

Fertilizers contain macronutrients such as nitrogen (N), phosphorus (P), and potassium (K), and micronutrients such as iron and magnesium. Nitrogen is responsible for the lush green growth of plants, phosphorus stimulates root growth and development, and potassium is mainly responsible for flower and fruit development. Fertilizers that have nitrogen, phosphorus and potassium are called “complete” fertilizers.

Fertilizers come in quick release (usually water-soluble) and slow release (extended release) types as well as different formats such as granular, spikes, and root feeders. Granular (or surface) fertilizers are useful for non-turf areas under trees (as turf tends to compete with trees for the nutrients.) When using granular fertilizer, be sure that the soil is watered before and after application. Spikes and root feeders (sub-surface) are advantageous as the fertilizer is applied below the surface where the tree roots are located. Many customers find tree spikes easy to use. When purchasing tree fertilizer spikes, keep in mind that there are different types for different trees. Use evergreen spikes for evergreens, fruit spikes for fruit trees and tree spikes for deciduous trees. The soil should be watered before using spikes. Always follow the directions on the label of the product you choose to use.

Newly planted trees generally do not require the use of a “complete” fertilizer during the first growing season, but will benefit from the use of a root stimulating fertilizer at the time of planting. Established trees (one year and older) will benefit from the use of a “complete” fertilizer on an annual basis. The best time to fertilize your trees is in the spring, before the new growth starts. By having the fertilizer in the ground in early spring, when the tree starts to grow the nutrients will be there for the roots to use. Do not fertilize your trees in late summer or early fall as this will stimulate new growth late in the season which will not have enough time to harden off before the freezing temperature arrives.

The best and most reliable way to know what type and amount of fertilizer your location requires is to have your soil analyzed. Soil sample kits (which are sent to AgSource Laboratories for analysis) are available through our customer service desk, or do-it-yourself? test kits are available for purchase in our garden center.

Pruning:

Pruning is an important part of maintaining the health and appearance of your tree. Trees, as living organisms, are unique and have different cycles. As such, what may be a good time to prune for one type of tree may put another type of tree at extreme risk for disease? To take out some of the guesswork, we have information sheets entitled “Pruning Trees and Shrubs” and “Pruning Evergreens”, which are very helpful. Knowing why, when, and how to prune will help you in caring for your tree.

Pruning deciduous trees:

The primary reasons to prune are for the health of the tree, appearance, and for safety. Keep in mind that every time you prune, you create a wound on the tree that needs to heal. If your tree has dead or diseased wood, pruning will help the tree heal and recover more quickly. (If you think your tree has a disease, feel free to contact Linder’s so that we can help you determine what would be the best course of action to take.) Additionally, removing branches that cross over or rub against another will help improve the health of the tree.

When pruning for appearance and/or safety, you will need to know when the best time to prune for your particular tree is. As stated earlier, pruning at the wrong time for some trees can greatly increase the risk of disease (or flower loss if your tree is one that flowers). Pruning for appearance includes shaping, thinning, and sucker removal. Pruning for safety reasons includes branch removal for power lines, weak branches that could fall and cause injury, and removal of branches that obscure vision of drivers on streets and driveways.

Making correct pruning cuts are as important as knowing why and when to prune. When removing a sizeable branch, it is recommended that it be completed in several steps to prevent the branch from tearing into the bark of the tree trunk. Do not make the cut flush with the trunk. Instead, locate the branch collar, which is the enlarged area at the base of the branch (see diagram below). You will need to make the final cut just beyond the branch collar leaving it intact. Do not leave any branch stubs, as this will only invite decay.

Step One: Make an undercut at #1, approximately 1/3rd to 1/2 way through the branch. This undercut is what will prevent the branch from tearing the bark on the trunk.

Step Two: Make a cut at #2 and cut through the entire branch. The majority of the branch (and weight) is now gone.

Step Three: Make the final cut at #3, leaving the branch collar intact on the trunk. Do not make the final cut flush with the trunk. Do not leave branch stubs.

A frequently asked question is whether or not to use sealer or paint on the tree wound. Studies have shown that using paint or sealant promotes decay. The tree will heal more quickly if allowed to heal unsealed. (The only exception to this is if you must prune elms or oaks during the months that they are most susceptible to disease transmission.) Please feel free to call Linders if you have questions about pruning.)

Pruning needled evergreens:

Evergreens generally require little to no pruning, except for removal of diseased, dead or broken branches. Some homeowners choose to shear their evergreens to help maintain a more formal shape. Keep in mind that evergreens tend to grow slowly, so be judicious in the amount you shear/prune. On some evergreens, once you have pruned to the point of seeing branches or bare wood, it may take a long time (if at all) for growth to start.

Evergreens generally put on a flush of growth in spring to early summer. It is during this flush of growth (the new finger like growth is called “candles”) that evergreens can be sheared. If you need to prune your evergreen you can shear off 1/3rd to 1/2 of the new candle growth before the new soft candles harden off. If you prune off all of the candles, the evergreen will need to re-sprout from old wood, which will take a long time (if at all). When pruning out dead or diseased branches from evergreen trees, you will follow the same pruning cut guidelines as outlined for deciduous trees, leaving the branch collar intact on the tree (see diagram and instructions above for pruning).

Do not prune your evergreen in late summer or fall. This late season pruning adds unnecessary stress to the tree as it prepares for winter.

Winter Care:

Your newly planted tree will require some care in the fall to protect it from winter damage. This damage can occur in the form of rabbit, rodent, and deer feeding as well as effects of winter sun and wind damage. There are some things you can do in the fall to prevent and/or minimize winter damage.

 Deciduous Trees: 1. Water your tree in the late fall up until the ground freezes, especially if it is a dry fall. Don’t over water, but follow the guidelines of approximately 1-inch of water per week until the ground freezes. This will prevent the tree from going into winter in a drought condition and will minimize potential dieback of branches. 2. Do not fertilize or prune your tree in the fall. Fertilizing and pruning stimulates new growth, which will not have time to harden off before freezing temperatures arrive. 3. Wrap your tree trunk in the fall from ground level up to the first main branch. Wrap your tree when the precipitation changes to snow; remove wrap in the spring when the grass starts to grow (do not leave tree wrap on throughout the growing season). Tree trunks need to be wrapped during the winter until the bark thickens and becomes “corky” which may take several years for some species of trees. Wrapping the trunk of the tree helps minimize rodent/rabbit damage as well as sunscald. Sunscald occurs in the winter when the winter sun warms the trunk of the tree, which allows the cells of the trunk to break out of “dormancy”. When the temperatures drop (due to cloud cover or at night) the tender cells die off, thereby causing “sunscald”. Wrapping trees minimizes this freeze-thaw-freeze cycle and protects plant cells in thin-skinned (young) tree trunks. 4. If you live in an area where there are deer, you may want to consider using a repellant product. Some products may help deter deer; some of the newer products are long lasting (will withstand several rainfalls before reapplication is needed). 5. If rabbit feeding is a serious problem, you might want to consider using a white plastic tree guard to keep rabbits away. Be sure that the plastic tree guard extends up to the first main branch of the tree or 24 inches above the anticipated snow line, whichever one is higher. Do not use a black plastic guard, as black absorbs the heat from the sun that intensifies sunscald potential.  Evergreen Trees: 1. Water your tree in the late fall up until the ground freezes, especially if it is a dry fall. Don’t over water, but follow the guidelines of approximately 1-inch of water per week until the ground freezes. This will prevent the tree from going into winter in a drought condition and will minimize the potential of winter burn. 2. Do not fertilize or prune your tree in the fall. Fertilizing and pruning stimulates new growth, which will not have time to harden off before freezing temperatures arrive. 3. If you have evergreens which have a high potential of winter burn (e.g. Dwarf Alberta Spruce) you may want to put up a burlap fence on the south and west facing sides of the tree. Keep the burlap fence at least 2 inches away from your evergreen tree. This will help minimize the loss of moisture from the needles (from the winter sun and wind). Remove the burlap fence in the spring. (Do not wrap your evergreen tree in burlap as burlap acts like a wick, which accelerates moisture loss from needles.) Also, you may want to consider using an anti-desiccant such as “Wilt Proof” which helps to seal the needles and reduce moisture loss. Keep in mind that you will need to reapply anti- desiccants mid-winter, as their effectiveness is short lived.

If you live in an area of deer or rabbit feeding, you may want to consider using a repellant. Some products may help deter deer and rabbits; some of the newer products are long lasting (will withstand several rainfalls before reapplication is needed).

If you have any questions regarding tree selection, planting, watering, fertilizing, pruning, and/or winter care please feel free to call us. We are here to assist you in making your outdoor home environment more pleasant and successful.