Caring For Your Trees

Trees are your most valuable landscape asset. Lawns are easily replaced, but trees are not. View the documents Tree Care Tips (PDF) and Mulching Tips (PDF).

Caring For Your Trees During a Drought


Even large trees need help to survive a drought. Stress from drought can impact a mature tree and cause it to die over the next several years.

It is recommended that you put a hose out by your tree and allow it to trickle at a slow rate for one to two hours minimum at least once a week in the early morning or late evening. You may also put a soaker hose around the base of the tree, or use a “gator” green slow release watering bag. For larger trees, multiple bags can be placed around the tree. You can find “gator” bags at your local Northbrook garden center or hardware store.
Village Employee Filling a Tree Gator Bag

Small Tree Maintenance


Small trees that are less than 5 years old need more frequent watering than mature trees. Water your small trees at least 2 or 3 times per week. Larger trees can be watered once every 10 days. The key is to water slowly and evenly for long periods of time to promote soaking as most of our soils are very dry.

Keeping grass around the base of the tree will deprive your tree of much needed water. As far as water and nutrients are concerned, the grass will out-compete the tree for water every time.

Using Mulch for Care


To allow for ample soil moisture along with moderate soil temperature, mulch is the best thing for your tree. A mulch ring to the drip-line of the tree (outer reach of branches) is ideal. However, if you don’t want such a large mulch ring, a minimum of 3 foot circumference around will suffice. Use a processed hardwood mulch as it decomposes slowly and has a rich, brown color that blends well with most landscapes.

You may also pickup some free wood chips at Northbrook Public Works anytime. The mulch is on the left side as you pull in the main driveway. Bring your own container and shovel.
Photo of Properly Mulched Tree (Courtesy of International Society of Arboriculture)

Fertilizers


Do not fertilize your tree during a drought period. Fertilizers are salt-based and will create a situation where more water is leached out of the tree and “burn” the tree. Wait until the tree is near dormancy, after September 15th and monitor rainfall totals. If we have a dry fall, it is best to wait until Spring 2013 to think about fertilization. Any fertilizer you use should be low in Nitrogen and Phosphorous and preferably time-released. A certified arborist may assist you with a fertilization program.

If normal rainfalls return, you do not need to continue an intense watering schedule. Also, as the days get shorter and the night time temperatures cooler, you may cut back on watering to once a week. It’s important to keep your tree watered until fall.

​Resident Consultations

The Public Works Department makes its arborists available to the public for many types of questions. Please either visit the Resident Consultation page or submit your question or request via the GONorthbrook service request system.