Planting Under Trees: There’s a Right Way, and a Wrong Way – You Get to Choose

by Kim Reiss,
Manager Sugar Creek Gardens

It’s easy and safe to garden under trees, as long as you keep a handful of guidelines in mind:

• Contrary to popular belief, most trees have fairly shallow roots, with some trees having roots that you can downright trip over, like Sugar Maples. Do some gentle exploratory digging to find out how much soil you have to work with before jamming a shovel into the soil under a tree.

• Never bring in soil to build up the soil level around the tree roots to increase your planting area. You might actually end up smothering tree roots that will grow even more shallow as they search for oxygen. Same with mulch – keep it to about 2.”

• Find the smallest sized plants you can – a quart vs. a gallon container — to keep the holes you have to dig less invasive.

• As in any garden, consider the site to find the best plants to match the needs of the site – dry shade? Deep shade? Wet, part-sun? Do your homework to save yourself some time and money.
Some of our favorite shade-loving groundcovers include monkey grass, ajuga, lily of the valley, vinca, ivy, sweet woodruff, and snow on the mountain. These are all fast spreaders and likely to follow you back in the house, so plant them in an area where you know they’ll be contained (i.e., by lawn). But all look fantastic when planted en masse, so you can’t go wrong.

Here are are my Top 5 favorite shade perennials for dry and wet conditions.

Dry shade: 1. Bishop’s Hat; 2. Hosta; 3. Lenten Rose; 4. Brunnera; 5. Hardy Begonia

Wet shade: 1. Hosta; 2. Ligularia; 3. Cardinal flower; 4. Turtlehead; 5. Cinnamon Fern.

No, it’s not a mistake that hosta ended up on both lists – it’s like the little black dress of the plant world — it can work just about anywhere (except maybe full sun).

So bottom line when planting under trees – you might not be able to fit a 3-gallon azalea under that 15-year-old dogwood tree because those tree roots are large and established. But some small hostas and brunnera might do the trick quite nicely.

Kim is a manager at Sugar Creek Gardens and is president of the St. Louis Hydrangea Society.