10 Gardening Gaffes to Avoid

What’s the difference between a new gardener and an experienced one? The experienced gardener has killed way more plants, the saying goes.

That truism speaks to the fact that gardening is a highly trial-and-error venture — and one where some plants are just going to struggle and die no matter what you do.

The good news is that the more you know and the more “right” things you learn to do, the less mayhem. In other words, messing up helps hammer home lessons that, if you pay attention, lead to more and more successes. Some of the best gardeners will admit to botching their way to botanical proficiency.

In case you’d rather learn from others instead of foul-up on your own, here are 10 of the most common gardening gaffes:

1. Underestimating how big a plant will get

The gaffe: Just about everyone who plants a plant is guilty of this one. Unlike furniture, plants don’t stay the same size after you place them. They keep growing until they die — some way faster and bigger than you expect.

The lesson: Pay attention to the heights and widths on plant labels and space at least that much. (Even those are estimates at fixed points in time, often 10 to 20 years out.) Then be prepared to start trimming, pruning and dividing once the plants reach their allotted sizes. Don’t wait for them to get way overgrown and then try to whack them back.

2. Pruning off the flower buds

The gaffe: This is usually the answer to the question, “Why didn’t my hydrangeas/azaleas/forsythias/etc. bloom?” Trees and shrubs that bloom in spring (generally before June) flower on branches that form their flower buds the fall before. If you whack those branches in the fall, winter or very early spring, you’ll cut off the buds that would’ve opened into the flowers.

The lesson: Wait until right after spring bloomers finish blooming to trim them. Definitely get to it no later than midsummer.

3. Killing plants by not watering enough

The gaffe: Even drought-tough plants need consistently damp soil until their roots grow enough to mine sufficient moisture from the soil. Until then, it’s up to you to make sure the soil around the roots stays damp. Rain seldom does the deed for you — at least not consistently.

New plants are at particular risk. While perennial flowers can establish reasonably well within two years, figure on three or four years before trees, shrubs and evergreens can go it alone.

New, relatively shallow-rooted plants such as annuals, vegetables and perennials benefit from soakings every two to four days in lieu of rain, while bigger trees, shrubs and evergreens can go every five to seven days — but with deeper soakings to account for their larger root systems.

The lesson: Your index finger — stuck a few inches into the soil — makes an excellent moisture meter.

Over Watering

4. Killing plants with too much water

The gaffe: Ironically, you can also kill plants by overwatering, although this is much more common with houseplants and with plants growing in pots without sufficient drainage holes in the bottom. For in-ground plants, the main excess-water threats are plants in poorly drained locations, unceasing rains and watering way too much and way too often.

The lesson: Improve the soil or build raised beds before planting in low-lying areas or lousy clay soil (or stick with plants that tolerate wet soil). Those solve the first two threats since you can’t regulate rainfall amounts.

Use that finger before watering. If the soil at the root level is already damp, put away the hose. For houseplants, wait until the soil is just going dry and the pot is noticeably lighter before watering.

5. Accidentally killing plants with sprays

The gaffe: Many a homeowner has burned leaves or killed whole plants by using the wrong spray, mixing too strong or applying the spray in the heat of a bright summer afternoon. One of the most common examples is killing grass by using a kill-everything herbicide (i.e. Roundup), thinking it was just supposed to kill weeds. Also common is damaging plants by failing to clean the sprayer after using an herbicide.

The lesson: Read those labels so you know what you’re using and how to safely use it. Consider dedicating different sprayers to insecticides, broadleaf weed-killers and kill-everything herbicides — or limit spraying altogether as much as you can.

6. Burning the lawn with fertilizer

The gaffe: Some chemical fertilizers are strong enough that if they’re applied to excess, the nitrogen in them can brown grass. Uneven applications can also cause streakiness.

Another all-too-common miscue is when DIYers dump granular fertilizer into their spreader and inadvertently spill some on the surrounding lawn. Those dumpings frequently cause brown lawn patches.

The lesson: Apply fertilizer according to listed amounts. Or switch to organic fertilizers or fertilizers that are high in slow-release nitrogen — both of which are far less likely to burn a lawn. Fill your spreaders on the driveway or other hard surfaces so you can sweep up spills.

Volcano mulching
Volcano mulching

7. Excessive mulching (a.k.a. volcano mulching)

The gaffe: Adding too much mulch around a tree. Volcano mulching is the term for placing mulch in a funnel-like mound that runs up against tree trunks. Yeah, you’ll see even professional landscapers do this, but it’s harmful to the trees by causing bark rot and by giving cover to rodents (mice, chipmunks and voles) that chew on tree bark.

A mulch of more than 3 to 4 inches — even if not right up against the trunk — is also detrimental by “stealing” rain in dry conditions and by reducing the amount of oxygen reaching tree roots.

The lesson: Keep mulch a few inches back away from tree trunks and limit mulch layers to no more than 4 inches. Two inches is plenty around perennials.

8. Messing with bulb foliage while it’s still green

The gaffe: Removing the bulb foliage early. The weeks after tulips, daffodils, hyacinths and other spring bulbs finish blooming are very important because that’s when the foliage takes in sunlight that provides energy to recharge the bulbs for next year’s bloom. You’ll interfere with that recharge by cutting off foliage that’s still green or by reducing the surface area by braiding or tying the leaves, as many people do to “neaten” the postbloom look.

The lesson: Don’t cut, braid or otherwise mess with spring-bulb foliage until it’s at least started to yellow — signaling that most of the season’s photosynthesis work has been completed.

9. Digging up plants that aren’t dead

The gaffe: In areas with subfreezing winters, you might think those crape myrtles, hardy hibiscus, butterfly bushes, figs and other late-to-leaf-out plants are dead when just about everything else is already green and growing. Know that some plants, especially those native to warmer climates, wait until the weather is consistently warm before springing back to life in late spring. Until then, these might look leafless and dead when they’re actually just still dormant.

The lesson: If you don’t know what’s normal for your plants, at least wait until the end of May or even mid-June before digging them out for dead. You can also tell by scratching a little bark off leafless woody-plant stems. If there’s green underneath, there’s a good chance the plant is still snoozing, not dead.

10. Planting too early

The gaffe: Cold-climate gardeners are eager to get those petunias, tomatoes and other summer annuals and veggies in the ground at the first sight of frost-free weather in spring. You might get a jump on the season some years, but many, many gardeners have watched their tender plants die when a frost follows a warm-up or two.

The lesson: Know your typical last-killing frost dates in spring and wait until at least then to plant frost-tender plants. At least wait until the all-time-late, frost-free time is approaching and check the 10-day forecast to be sure nothing is even close to a freeze before planting. Just because garden centers and home centers are selling tender plants doesn’t mean they should go in the ground then.

About The Author

George Weigel is the author of “50 American Public Gardens You Really Ought to See.” This article is provided as an educational and inspirational service of the National Garden Bureau and its members and was originally published on the NGB website.