Tree Care Diary – August

Light and shade filtering through a tree


Too hot? Plan now for shade trees in your yard


Who is this tree care advice for?

Our monthly Diary is created for individuals and business property owners in USA who may have one or more trees on their land. Mature trees can add around 10% to the value of your property say the USDA Forest Service; BUT only if they are kept in good condition, say Moneysense. It’s easy to see that a little love and attention from time to time will benefit both your trees and your property’s appraised value.

If you have any questions about any of the advice offered here, please seek the advice of your local arborist. Call us at Tree Top Pros to talk to one in your city.


Planning for shade trees in early August

In most states, August is the hottest month of the year. So it’s a great time to explore exactly where in your garden you should plant a new shade tree or two. Well-placed shade trees near your property can save you between 10% and 40% in summer air-conditioning cooling bills according to a recent report from the Arbor Day Foundation. This range of savings is dependent on the positioning and number of shade trees planted.

In August the sun is strongest between 1 p.m. and 3 p.m. This is when you need the shade the most. To prepare for planting a shade tree sapling, it’s best to track the shadow thrown by the sun during these hours and a little before and after. On a clear day in early August, use a tall cane or straight stick to determine the direction of shade every hour between, say, 12 noon and 4 p.m. From the shadow made by the stick at different times of the afternoon, you can choose a planting position that will give you the maximum shade for your home and yard when the sun is at its strongest.

If you don’t have the time to do this, the best positions are usually two shade trees to the South of your property and one to the West.

Now August is rarely the best time of year to actually plant a young tree so you’re just at the beginning of the process. But at least you are now able to fix your ideal planting site/s. Be sure to avoid drainage lines, pipes which a large tree’s roots can easily invade and damage. And steer clear of your home’s foundations too by not placing the tree too close to your home.

We’ll cover best practices for planting trees in our next Tree Care Diary post (September). Generally, September and October are the best months to plant trees i.e. when the hottest days of summer are behind us and yet when the ground is still relatively warm.

Remember that a large shade tree can actively cool the surrounding air as a result of the evaporation of water from its leaves during transpiration. NC State University’s Department of Horticultural Research confirm that just one tree can have the same cooling effect as up to 10 single room air conditioning units working 20 hrs out of 24. Hard to believe but here is their link to prove it: 

So if you have the space, plan to plant more than one shade tree for an extra outdoor cooling effect.


Watering your trees

Lady's hands watering a treeOK, it’s August but that doesn’t automatically mean you need to drain the local reservoir watering your trees. Large, mature trees are unlikely to need watering unless there’s a severe drought. Most will have deep roots that can reach moisture in the ground far below the surface.

Over-watering every tree is a commonly-seen mistake. Soil that is saturated with water will not allow adequate oxygen to reach the soil and roots. The organisms in the soil that make it fertile drown with too much water and the tree’s roots die back. Moist (rather than soaked) is better because it will still allow sufficient oxygen for both the soil and roots to thrive. Signs of over-watering include leaves drooping down and turning dark brown or black and even defoliation.

Instead, focus your attention and hosepipe on newly planted or young trees less than two years old. For these, keep your soil moist, not soggy. Usually 30 seconds of water for each tree delivered from a hose with a diffuser attachment is enough. The reach of a tree’s branches reflect the size of its root system. So when watering, don’t just soak the bottom of the trunk.

No matter how old or large your tree, look for signs of lack of water.  If your tree’s leaves are curling upwards or inwards and starting to turn brown this month, then the soil surrounding its roots is too dry.


Tidy up your tree mulch

The loose material in the mulch can easily be scattered by birds and small mammals looking for bugs and grubs lurking underneath. As your mulch will slow the rate of evaporation around the tree and keep the soil cooler in the hotter times of the day. So tidy up any mulching that you established earlier in the year – see our March Diary entry ‘March is for mulching’ for more details. Keep the mulch circle out to the drip line of the tree, keep it away from the root flare (that’s the base of the trunk at ground) and keep at no more than 3 inches deep. Remember, no volcano-mulching around the trunk!


Fertilizing your trees

It’s unwise to fertilize trees now apart from one or two exceptions mentioned below. Applying fertilizer will result in late season growth. This is unlikely to harden off in time and may not go dormant in winter. Frost will probably kill this new growth which may, in turn, cause long-term damage to the health of your tree.

Continue to monitor your palm trees this month. The upper fronds should all be a glossy green. If these appear to be yellowing prematurely then consider a slow-release fertilizer containing Potassium and Magnesium. See our Summer Care for Palm Trees Diary entry.

August is the time for the third (of four) applications of fertilizer for citrus trees in the year. (Feb, May, Aug and Oct).


Tree Pest watch

Inspect your plants for disease or infestations. Trees that are dry and stressed in the summer heat can be more prone to molds, diseases, pests and fungi. Check your trees for signs of discolored leaves and holes. Remove any infected leaves or branches to reduce the problem for next year. Before you do, make notes and keep track of when pest problems occur throughout the year, so you can better prepare and prevent them in the future.


Tree Pruning in August

Man, its hot. So put the shears and pruning saws away this month. You could in theory remove water sprouts, dead branches, crossing branches and suckers; these are all non-season dependent. However, this can easily wait until a slightly cooler month, in our view.

For the majority of trees, it’s too already late to do any ‘shaping’ or cosmetic pruning. Bear in mind that pruning actually encourages new growth. Any late growth spurred on by late pruning is prone to damage later on in the year during less clement weather and during frosts.




Kindly Note: The accuracy of this calendar and timings shared within it cannot be guaranteed. States in the USA are at different latitudes, longitudes and have varying elevations. This makes the general advice we give hard to fit all states the same. Compounding these differences are the typical tree species sets between states. Furthermore, each state has its own weather patterns and levels of rainfall. All the calendar can do is broadly summarize best practice care for your trees. We therefore suggest that you consult your local arborist for more specific insights and advice relevant for your particular location.

Tree Care Diary - September
Tree Care Diary - July