The best, cheapest, and easiest way to fertilize a tree is to mulch it properly. Mixing leaves into the mulch each fall adds a lot of nutrients.

If your trees are healthy, use the leaves from your lawn that have been chopped into small pieces with the mower. If the leaves appear to be unhealthy or moldy, then don’t mix them in your mulch.


Mulch around a tree

Mulch provides the nutrients needed by trees

I think my tree needs a fertilizer.  What should I do?

There are times when fertilizers are needed. The best way to figure out what kind of fertilizer your tree needs is to test your soil. The results will also tell you how often and when to apply the fertilizer.

An additional benefit of getting a soil test is that it provides helpful information on how to manage other plants in your yard.
Often people spread the fertilizer over the grass around the tree, but the result is better grass and weeds rather than improved tree growth. Getting fertilizer below the grass to the roots of trees is important and not difficult. Many licensed tree care companies offer this service, but it can also be done on your own – follow the steps below.


Soil testing

Soil testing



How to apply fertilizer to your trees:

  • Test your soil before fertilizing to determine what nutrients are needed, how much to apply and when.
  • Choose one of the following 3 methods of application:
    • Fertilizer stakes:  Push fertilizer stakes into the ground below the roots of the grass. You will need gloves and a mallet to hammer the stakes about 10 inches into the ground.
    • Granular fertilizer:  Dig or drill 10-inch deep holes into the soil. Anything that can be used to plant flower bulbs will work well to dig the holes. Some home and garden stores rent or sell small augers. Place the granular fertilizer into the holes.
    • Liquid fertilizer: Inject liquid fertilizer 8-10 inches below the surface into the soil with a probe. This is the preferred method of the pros, but unrealistic for most homeowners without the special tools.
  • Based on the results of the soil test, head to your local home improvement store to buy the fertilizer. Tree fertilizer is not the same as fertilizer for grass. Look for “Deciduous Tree” or “Evergreen” and water insoluble nitrogen (WIN) on the label.
  • Use a slow-release fertilizer to protect the quality of water in our watersheds.
  • Always follow the directions on the label of the fertilizer.


Fairfax County Government Tree Fertilization Diagram

Fairfax County Government Tree Fertilization Diagram


When to apply fertilizer:

  • Follow the directions from the results of your soil test.
  • Time it right:
    • In October or November to encourage root development; or
    • In March or April to encourage tip and leaf growth.
  • Never fertilize a newly planted tree – mulch is best for the first 3-4 years after planting.


Where to apply the fertilizer:

  • Put fertilizer stakes or dig the holes for granular fertilizer under the branches of the tree in a grid formation, about every 2 ft.
  • Start at the outside, or the ends of the branches, and go in towards the stem of the tree.
  • For all trees, stay at least 4 feet away from the trunk of the tree and work out to the tips of the branches.
Posted by admin in Fall


Weeds use a lot of water and nutrients that your trees need, so we recommend getting rid of weeds from around your tree.  If you have questions about lawn weeds, visit our lawn care website. 

The best method for weed removal is hand pulling and disposing of the weeds in your yard waste pickup or compost bin. For poison ivy, check the recommendations below before starting.


Yard trim compost bins

Montgomery County DEP distributes yard trim compost bins for free. Learn more.


Weeds are not the only plants that compete with your trees. Flowers, shrubs, ornamental grasses, and vines all use water and nutrients, prevent sunlight from reaching the trunk, and create a moist environment for bacteria and fungi that can harm the tree.  The mulch around the tree should be at least 3 feet out from the trunk and be free of any other plants.

Vines are another common weed problem. They require special handling.

  • Don’t pull vines off trees. Instead, cut out a 6-inch chunk of the stems of vines. Let the vines die and gradually fall off the tree.
  • You can cut vines any time of year. If the vines are cut in the fall, the dying leaves are less noticeable. Don’t pull them off. Instead, cut out a chunk of the vine stem and let them die…they will gradually fall off.
  • While poison ivy is a hazard if it gets on our skin, it happens to be native, beneficial to birds, and not harmful to trees. If there is no risk of contact with people, then leave the poison ivy. If you choose to remove poison ivy, handle with great care year-round. The oil in the vine, roots, leaves, and berries is an allergen that can cause severe rashes, blisters, and itching. The oil can stay on clothing and gloves for a long time.
Posted by admin in Spring, Summer

Deer Protection

In Montgomery County, most newly planted trees must be protected from deer. White-tailed deer damage young trees in two different ways:

  • They eat, or browse on the trees especially the twigs and buds; and
  • The bucks, or male deer, rub their antlers along the trunk, or stem, and scrape off the tree’s bark. The deer are instinctively rubbing velvet, or skin, off their antlers.



Both browsing and rubbing by deer kills trees. Therefore, protecting your trees is important.

One of the easiest way to protect newly planted trees from browsing is to plant trees that are taller than 6 feet. Deer may still eat some lower branches but they will not be able to reach the top of the tree allowing the tree to continue to grow.

Deer protector

Deer protector

For smaller trees, install chicken wire or deer netting around each tree or groups of trees. The wire or netting should be at least 5 feet tall.

There are several ways to stop bucks from rubbing the trunks. The best protection is to install a cage around the tree trunk using heavy-duty plastic mesh. Chicken wire will also work. The mesh or wire should be at least 4-feet tall and anchored to the ground so the deer cannot push it out of the way. Another way is to install two pieces of 4-foot rebar on opposite sides of the stem, or trunk, and as close to the trunk as possible.

Posted by admin in Fall, Spring, Summer, Winter


Newly planted and young trees need extra water during hot, dry summer months. You can help young trees flourish and grow by providing 25 gallons of water each week between the 4th of July and Labor Day.

There are several different methods for watering young trees. Each way is effective so choose the method that’s most convenient for you. It is important to water newly planted and young trees regularly during the summer.


How to water newly planted trees – the first six weeks

During the first six weeks after planting, your new shade trees need a lot of water! When they were planted, the trees were watered to settle the rootball, fill air pockets with soil, and provide moisture to the roots. The Tree Montgomery program does not require that you water your new shade trees. However, if you can, it helps the newly transplanted trees establish healthy root systems and start growing.

Watering a newly planted tree is very important

Watering a newly planted tree is very important

Now that your tree or trees have been planted we recommend that you follow this watering schedule during the first six weeks after planting. If it rains enough to soak the ground, you can skip the next watering.

  • During first and second week following transplanting – water 3 times each week
  • During the third and fourth weeks following transplanting – water 2 times each week
  • During the fifth and six weeks following transplanting – water 1 time each week
  • During the first two summers, water at least once a week between the Fourth of July and Labor Day
Water using Soaker Hoses

A soaker hose is designed to let water slowly seep out along the length of the hose. This saturates the soil around the tree by mimicking a gentle day-long rain. It’s convenient because you can leave a soaker hose in place during the summer. You can also cover the soaker hose with mulch to hide the hose and help disperse and conserve water.

Check the hose regularly to make sure the water drips out gradually along most of the length of the hose. Water should not flow continuously from the hose; if it does, reduce the water pressure by turning back the faucet.

For newly planted trees, place the soaker hose in the mulch ring. Water each new tree for about a half hour. For larger trees, place the hose in the mulch ring, or about four feet from the trunk, and leave the water on for about one hour. Timers to automatically turn your outdoor faucet off are available on-line or at lawn and garden shops.

Water using Garden Hoses

There are at least two ways to water using a garden hose.

Water with a slow drip from your garden hose. Turn on the water, then turn the pressure down (nearly to off) so that the water slowly drips out – literally one drop at a time. This mimics a slow gentle rain. For recently planted trees, place the end of the hose in the mulch ring and leave the water dripping on for about an hour. For older trees, place the hose about four feet from the trunk and leave the water dripping for about one hour on one side, then switch the hose to the other side of the tree for another hour. Timers to automatically turn your outdoor faucet off are available on-line or at lawn and garden shops.

Water newly planted trees from your garden hose without the nozzle. This mimics a summer rain storm. Remove the nozzle from the end of your hose. Using a watch and a bucket, determine how long it takes to fill the bucket as many times as needed for 25 gallons. For example, if you have a 5-gallon bucket, how long does it take the garden hose to fill the bucket 5 times? Once you know how long it takes, then water each newly planted tree, within the ring of mulch, for the time needed for 25 gallons. This generally does not work on hillsides because the water runs down the hill too quickly.

Do not water with a spray nozzle or sprinkler from your hose – this gets water to the surface but very little gets below the grass to the tree roots.

Water using buckets with pin holes in the bottom

This is an easy way to make your own soaker. First, gathers some buckets or jugs and make sure they are empty and clean. Then pierce the bottom of each with 5-10 tiny holes to allow water to drip out gradually. For newly planted trees, place the full buckets in the mulch ring. For older trees, place the full buckets about 4 feet from the trunk. Check to ensure that they empty in several hours.

Remember to refill your containers as many times as necessary to give your young trees 25 gallons of water.

Also, we recommend placing rocks or a brick in the bottom of the buckets to keep them from blowing away or falling over.

Water using Specialized Watering Bags, or “Gator” Bags

Gator bags use the same slow-drip technique as soaker hoses or buckets. There are several styles available on-line or at lawn and garden shops. Most are designed to be used on small trees.

Seattle Department of Transportation Photo, Flickr CC

Gator Bag. Seattle Department of Transportation Photo, Flickr CC

Read the label for how many gallons the bag holds. Install the gator bag and then fill it with water. Check to make sure the water empties in several hours. Refill the bags to give each tree 25 gallons of water during each watering.

Remove the bag when watering is complete. If left on between waterings, these bags promote bacteria and fungus and can harbor critters, potentially causing problems for your trees.

Need to know when to water?

We’ll tell you. Tree Montgomery sends out watering alerts throughout the summer, on Facebook and Twitter. Follow @MyGreenMontgomery on Facebook and @MyGreenMC on Twitter for watering updates on Thursdays throughout the spring and summer.

Posted by admin in Spring, Summer


Mulch is great for trees. It helps keep the weeds out, adds nutrients, protects trees from weedwackers, and helps trees survive dry weather and extreme temperatures. The list goes on and on.

We recommend following the Rule of 3:

  • A ring of mulch, 3 inches deep;
  • At least 3 feet wide around the tree; and
  • The ring should start about 3 inches from the trunk so the mulch doesn’t touch the stem.

Say no to the mulch volcano – too much mulch around the tree and touching the stem can actually kill your trees!


Download our mulch guide  to learn the right way to mulch.

Download a mulch meter – a pocket guide to measuring the right depth of mulch.


A tree with a healthy amount of mulch

A tree with a healthy amount of mulch

Posted by admin in Fall, Summer