Denny's Soapbox

Overwatering – A common problem

As we go through summer, an age-old problem returns. I call this problem “killing with kindness”.

Plants installed within the last year run a serious risk of being overwatered. Nine of every 10 plants that I check in homeowners’ landscapes have this problem. Water seems to be the magic potion that we feel will get our new plantings off to a good start.

Newly installed plants take at least a full season to establish roots, but all plants, need to dry between waterings. They cannot be kept continually wet. The problem is further compounded because overwatered plants show the same symptoms as underwatered plants.

With many trees and shrubs, the edges of the leaves turn brown, when overwatered and then the plants hold their brown leaves attached to the branches. Broadleaf evergreens such as blue and china hollies will have the leaves turn black and fall off. Needled evergreens that have been killed with kindness will stay green for five to six months after they’ve died. That’s why needled evergreens are sometime referred to as the ‘living dead’. Just look how long a cut Christmas tree stays green.

When to Water

Using a calendar is a NO-NO! There are too many considerations to say “I’ll water once a week”. There’s rainfall, heat, humidity, wind, and type of soil to factor in.

The safest way to determine when to water plants is a garden trowel. Take the trowel and dig down 3 to 4 inches around the plant. If there’s moisture in that soil, wait to water until that soil is dry.

Don’t assume because one plant is dry, they all are. Check all the different areas of your landscape before watering.

If you have a sprinkler system that covers plant beds, set the timer on manual for those plant zones. Check those beds before watering.

How Much to Water

There are two ways most homeowners water. Some take the hose and put water on individual plants. Others use a sprinkler.

When watering individual plants, the soil between those plants stays dry causing freshly applied water around your plants to wick into the dry soil necessitating more frequent waterings.

A sprinkler waters the entire area: many are adjustable to various beds.

Place a straight sided glass in the area and let it fill ½-inch to 1 inch of water at a time. Then keep checking on the soil to see when you have to repeat waterings.

For individual newly installed trees, place your hose in the mulch ring near the trunk and let the water trickle for approximately an hour.

One Final Note

Certain plants wilt from the heat when planted in areas that receive lots of sun. Leading the list would be Florida dogwood, large leaf hydrangeas, and impatiens.

Mulch does help keep moisture in the soil. If using hardwood mulch, loosen it monthly with a cultivator, allowing rain or your hose to get moisture to the soil.

Finally, remember that all plants will do much better in soil kept on the drier side.