To deal with drought in your garden, water with precision

Drought is probably coming for your garden. You may notice it first when lawn grass is turning brown, but other plants are in the line of focus. Droughts can cause long-term damage to trees, shrubs and other plants, said Sharon Yiesla, plant knowledge specialist at the Plant Clinic at The Morton Arboretum in Lisle. They all need your help to get enough water to survive this one.

Most of northern Illinois is in moderate to severe drought conditions, according to the US Drought Monitor website. At the Arboretum, this spring saw only about half as much rain as the drought year of 2012. In fact, it was the driest spring since 1936, when a national drought created the Dust Bowl on the Great Plains. .

Although early July brought 2 to 3 inches of rain to parts of the Chicago region, it wasn’t enough to end the drought and the plants are still under threat.

Understanding how drought affects each type of plant can help you make good choices about where to focus your watering efforts, Yiesla said. Here’s what you should know.

Meadows: Without regular watering, lawn grasses will go dormant. The blades of grass die, turning brown and dry, but the roots usually survive. This is a normal process, Yiesla said. In the wild, grasses go dormant every year in the dry months of summer. We keep the abnormally green turf grass in our lawns by watering.

To conserve water in a drought year, let the lawn do what comes naturally and go dormant. Only give it about 1/2 inch of water every 2 to 3 weeks enough to keep the root system alive without the lawn staying green. If the drought becomes even more severe and the roots die, it will be easier to replace a lawn than to replace other plants such as trees and shrubs.

Trees: Drought damage can affect trees for years to come. We’ve seen trees die six or seven years later from the effects of the 2012 drought, Yiesla said. It’s hard to see the impact at first because the damage is happening underground: As the soil dries out, the fine feeder roots that collect all the water for the tree begin to die. If a tree loses much of its root system, it will no longer be able to absorb enough water even when the rain returns. A lack of water flowing from the roots down to the leaves and stems will affect every life process of the tree.

Trees need water in the summer to form their leaves and flower buds for next year, she said. Drought-stressed trees may have fewer leaves and flowers next year. Trees will struggle to form fruit later in the summer and will also be more vulnerable to pests and disease.

Since mature trees improve property values ​​and provide shade, watering them is a priority. To keep feeder roots alive, focus on watering up to the drip line—in other words, water the area of ​​soil covered by tree branches, Yiesla said. Pay special attention to watering newly planted trees.

Water the trees and all plants thoroughly, so that the water seeps 5 to 6 inches into the soil. This will encourage the feeder roots to grow longer and deeper, increasing the plants water holding capacity. Mulch can help by keeping water from evaporating from the soil surface. Water well, then spread a layer of mulch 3 to 4 inches deep over a large area around the tree. The mulched area should extend at least 3 feet from the trunk. The more root area you can cover, the better, Yiesla said.

An effect of drought on trees is very visible. They are likely to change color soon and let their leaves dry and fall off, she said. They hibernate early to try and save themselves from drought.

Shrubs: Although some shrubs, such as yews, are usually hardy enough to survive most droughts, others, such as hydrangeas, are shallow-rooted and vulnerable. This summer’s drought-stressed flowering shrubs will struggle to flower next spring. Make sure all the roots of your shrubs are covered in a layer of mulch and water them regularly. Prioritize systems installed in the last two years.

Perennials: Plants labeled drought tolerant will also need watering. Some plants may have brown, burnt leaves and some may die. Native prairie plants are often described as drought tolerant, but only after they have matured and developed a root system large enough to store water. Those planted within the last couple of years will still need watering. If drought continues throughout the summer, even prairie plants can be stunted, with few flowers.

Vegetables: Many vegetable plants, such as tomatoes and peppers, evolved in rainy subtropical regions and need their soil to be consistently and evenly moist. Make sure your beds are mulched to keep them in water, Yiesla said. Check the soil often and water enough to keep it moist in the top 6 inches. Plants will draw more water from the soil as they grow.

For tree and plant recommendations, contact the Plant Clinic at The Morton Arboretum (630-719-2424, mortonarb.org/plant-clinicOR plantclinic@mortonarb.org). Beth Botts is a writer at the Arboretum.