Common Gardening Mistakes You May Be Making

Landscaping Peter Greenway / EyeEm/EyeEm/Getty Images Even the greenest of thumbs get it wrong sometimes. by Grace Gallagher Updated: Feb. 20, 2024 Originally Published: July 22, 2022

Jacky Parker Photography/Moment/Getty Images Gardening can feel like a game of chance: one of your plants is thriving while its neighbor wilts. Stephanie Fox of @loving_my_gardeningtips runs down the most common mistake gardeners make when growing these popular varieties.

Planting new shrubs too close to each other

“Within a couple of years you will have to move one of them,” Fox says. While you wait for them to fill out, fill in the space with hardy or half-hardy annuals like Cosmos. Catherine Falls Commercial/Moment/Getty Images

Cutting peonies

“Never prune your peonies,” Fox says. “Let them die down gradually.” When you cut peonies, it doesn’t prompt a second round of growth. Instead it can leave the plant weak as peonies get energy from their leaves. Wait until fall to cut if you can. Shutterstock

Not knowing which type of clematis you have

“Your clematises fall into different groups for pruning; find out which group yours belong too,” Fox says. There are over 300 different species of this plant, which is in the buttercup family. Shutterstock

Not giving hydrangeas the right light

“Hydrangeas need morning sun and afternoon shade,” Fox says. This means you’ll have to study your yard at different times of day when selecting the best spot for a hydrangea bush. Shutterstock

Fertilizing Lily of the Nile

“Don’t feed your Agapanthus: their root system needs to struggle and they love their roots being in a cramped position,” Fox says. Because they like restricted roots, they often do best in pots. Hristo Shanov / 500px/Getty Images

Watering in the afternoon

“Never water in full sun,” Fox says, adding that early morning or evening is best. Pots need extra watering, too, as potting soil is lighter and more compact than ground soil, and dries out more quickly. rbkomar/Moment/Getty Images

Not pruning lavender

“As soon as your lavender flowers have finished cut them down fairly hard to avoid leggy woody lavender,” Fox says. Some woodiness may be inevitable, but cutting it back (and on a slope) will help the plant last longer. Shutterstock

Not properly supporting tomatoes

Tomatoes are pretty easy to grow once they get going, but they really need support via stakes or tomato cages to thrive. Otherwise, they’re too top-heavy and will fall or the stalks will break. Shutterstock

Planting herbs together

It’s best to divide herbs into their types so you can give them the best conditions. For example, Mediterranean herbs like sage, oregano, and thyme can grow together as they all like full sun. Chives or tarragon prefer shadier spots. Shutterstock

Skipping mulch

Maybe you don’t like the look of it, or it seems like an unnecessary step, but mulch is key because it acts as an insulator, keeping roots at the optimal temperature depending on the season. Cavan Images/Cavan/Getty Images