Gardening 101

Garden Resiliency in Drought and Deluges

Shade cloth

In the southeastern United States, we have always dealt with short term droughts interspersed with copious rainfall. Climatologists are predicting this will continue but with more of both. Since dry heat and heavy rainfall events in the last couple of years have already tested our landscapes, how do we build resiliency into our lawns and gardens to withstand these extremes?

When It’s Hot and Dry in the Garden

Plants have varying degrees of tolerance for having dry or wet roots, so choosing the right plant for the right place is always the first step. This includes trees and shrubs. They may be slower to die than an annual or herbaceous perennial, but three weeks of no rain in a hot summer can severely damage roots especially if the plants are at the top of the slope, in full sun, or near concrete. Give these sun-loving plants a good 2 to 3-inch layer of mulch and consider having a drip irrigation system ready if needed.

Cistern

A cistern / Jeana Myers

Drip irrigation lines are more efficient than overhead or pop up sprinklers, and can be repaired if they leak, unlike soaker hoses. They do require a pressure regulator but can be nicely customized to your garden, fit with a timer, and provide water directly to the rooting area, which minimizes evaporative loss and saves you money. You can put a light layer of mulch over the lines to make them invisible.

Water barrels and cisterns are excellent for capturing rain, but try to install the largest one your space and budget will allow. A 50-gallon barrel will only water a 10 by 10-foot area for one week at the recommended rate of 1 inch of water. But a 1-inch rainfall will easily fill the two 350-gallon tanks nestled up against our small house. Watering from a cistern will usually require a pump to provide pressure equal to a city water line.

Shade cloth

Shade cloth / Jeana Myers

Offer afternoon shade to your landscape via trees, arbors with vines, shade cloths, and fencing. We need more trees to keep our landscapes cool, so if a large tree won’t fit, consider planting several smaller trees – maybe some with edible fruit.

Fescue lawns generally require irrigation during the heat of summer, so if you want to move towards fewer water expenditures, a warm-season lawn like Bermuda, zoysia or centipede may be a good option.

When It’s Soaking Wet in the Garden

We have less control over heavy rains than we do drought, so prior planning is important. How your landscape is contoured will determine water flow, and anything you can do to slow that movement will protect your soil and plants from erosion. Arrange planting beds against the flow of water and consider planting swaths of fibrous-rooted plants like ornamental grasses to act as water dams and filters. Tree and shrub cover reduce droplet impact and improve the infiltration of water.

Slowing water

Grasses, groundcovers and stone slow down water flow / Jeana Myers

Flower and vegetable beds should be raised 4 to 8 inches to allow for root drainage. Trees and shrubs need to be planted above grade as well because the soil will settle over time and poor drainage often leads to root disease or drowning. Try to raise the general area around a tree, rather than just a tiny hill, to ensure the tree roots will have a well-drained area to grow for many years. Container gardens are always an option as they drain quickly.

Mulches protect the soil but keep applications to 2 to 3 inches to avoid a shortage of air to the roots. Shredded mulch and pine straw tend to stay in place better than wood chips when on a slope, however, shredded mulch may take longer to dry as it packs tighter. Small to mid-sized stones work well as mulch with heat-loving plants although they will still require the occasional weeding. Cover crops such as crimson clover and annual rye can provide ground protection during cool months in areas where other plants are not growing.

Building swales and rain gardens to capture and help with infiltration may be useful where large amounts of water tend to flow. Rain gardens support plants that tolerate short term excesses of water, but should completely drain in 24 hours. They can be both functional and quite beautiful.

Rain garden

Rain garden

The more trees, shrubs, and plants we have in our landscapes, the more cooling and infiltration impact we get. This is great news for those of us who love to garden – plant more! And do some planning for those super dry and super wet days we are sure to have here in the southeast.

Featured image – Shade cloth protects plants for sun and from too much water / Jeana Myers

Jeana Myers, PhD, is the Horticulture Agent for Wake County. For gardening questions, contact the Extension Master Gardeners of Wake County at 919-250-1084 or email [email protected]