8 Common Mistakes Every New Gardener Makes

Even pros mess up. Our garden writers share their most epic flubs and the lessons they learned. So the next time you commit a backyard blunder, you can rest assured—you’re in good company.

new gardener, Rookie Saw May 14
Some native plants can be aggressive.

Right Plant, Wrong Place

Seven years ago, we began to transform much of our 3 acres of lawn into meadows and prairie using native plants. One of the first native plants we added was sawtooth sunflower. It’s native to our area and beautiful, with clusters of yellow flowers atop tall, slender, sturdy stalks. Pollinators love it! But in a few short years, this plant began to take over our small prairies, choking out other native plants. We learned a very valuable (and labor-intensive) new gardener lesson about the importance of understanding that some native plants can be aggressive in the wrong setting. We spent more time removing this aggressive native than doing any other task associated with our prairie transformation.

Native plants are wonderful, and so very important for wildlife. But when researching what plants are native to your area, be sure to understand how each plant behaves, and whether it’s actually the right plant for your application.  —Kenn and Kimberly Kaufman

Discover 7 perennial plant mistakes you should never make.

new gardener, Rookie Wrong Cut May 14
Don’t prune off next year’s hydrangea flowers.

Pruning at the Wrong Time

Unable to resist the siren song of the beautiful bigleaf hydrangea at my local plant nursery, I shelled out a pretty penny and bought a couple shrubs to plant in late spring. A few months later, after a successful bloom, I diligently made sure that I cut them down, as I do with all of my perennials before winter sets in. When spring returned, I eagerly awaited a flush of new flowers. Imagine my surprise when all that came up were horribly sad-looking, shin-high shrubs with only a few green leaves.

After doing my homework, I realized I had snipped off every last new bud that had developed the fall before! It turns out bigleaf hydrangeas bloom on old wood. Lesson learned for this instantly reformed new gardener!  —Rachael Liska

Psst—here’s how to change the color of your hydrangeas.

new gardener Rookie Hibiscus May 14
Make sure your shrubs don’t take over your house.

Fast-Growing Plants Aren’t Always Best

When we bought our first house, I headed to the nurseries and grabbed anything that caught my eye. Unfortunately, I made new gardener mistakes such as putting fast-growing shrubs too close to the house (hello, hibiscus that needs to be pruned pretty much every week!). I also put in plants that are invasive in my area, and spent the next few years trying to uproot Florida space invaders such as Mexican petunia (Ruellia simplex).

With a few of these errors under my belt, I learned that I needed to focus on native plants that would thrive in my yard. In the end, those smart choices are better for the ecosystem, attract an abundance of wildlife and help limit the amount of time I spend on watering and pruning. —Jill Staake

See 12 mistakes you’re making with your tomato garden.

Rookie Mosquito May 14
Drain standing water so mosquitoes don’t lay eggs.

Growing a Mosquito Farm

As a new gardener dreaming of summer nights and the sweet fragrance of huge creamy white flowers, I put an aquatic American lotus plant in a big ceramic pot of water on the patio.  I didn’t reckon on egg-laying mosquito swarms finding the water and turning it into an “Anopheles breeding pit,” as my son dubbed it.

Those romantic summer nights on the patio became slapping fests as the mosquitoes hatched in droves. I gave the lotus away, drilled drainage holes in the pot and planted geraniums in it instead. —Sally Roth

Discover 8 mosquito-repelling plants you need in your backyard ASAP.

Rookie Whisper Love May 14 (1)
Give your seedlings room to grow.

Not Thinning Your Seedlings

I live in Wyoming, 7,000 feet above sea level, where plants are precious. I sometimes whisper encouragement to my tiny tomatoes and jalapeños. That’s why I just can’t thin my darling seedlings, even though I know they can’t all survive, and I know some must go for any to thrive. So I let too many grow, resulting in stunted beans and pencil-thin carrots.

I vow to thin next season. But when early summer comes, I stare at those little plants and think, ‘Maybe they’ll make it this year.’  —Christine Peterson

No green thumb? Check out the top 10 low maintenance perennials.

Rookie Grass May 14
Fresh grass clippings can burn young plants.

Using the Wrong Mulch

After planting hundreds of tree seedlings, I found some freshly bagged grass clippings on the curb and distributed them around dozens of the seedlings as a mulch. The mulched tree seedlings were the only ones that died. Why? The grass clippings were fresh, so they built up heat and killed the tender trunks. —Luke Miller

Here’s everything you need to know about mulch.

Rookie Tomato May 14
Tomato seedlings can grow too large if you plant them too soon.

Starting Seeds Too Early

I started my tomato seeds indoors on Valentine’s Day, as always—eight weeks before they go outside at about 6 inches tall. I wasn’t counting on a spring much colder than usual, with frost every night for a full month beyond the last frost date. Our living room looked like a jungle, with 2-foot-tall tomato plants crammed on every windowsill. —Sally Roth

Grow more resilient flowers with the top 10 plants you can’t kill.

new gardener, Rookie Opener May 14
Is that mystery flower a weed or a perennial?

Mixing up Weeds vs Perennials

When I purchased my house, the previous owner said it had a perennial garden, and she even left me a hand-drawn map identifying the plants. One warm spring day I spent five hours weeding and was so proud of myself as a new gardener. Until my neighbor leaned over the fence.

“Why did you pull out all the perennials and leave the weeds?” she asked.

Yup. I thought the flowering plants were perennials, so I’d yanked out all the not-yet-in-bloom plants. The lesson learned: Read the map and look up any plants you cannot identify so you don’t destroy your garden.

I frantically tried to replant the stuff I’d pulled out, which was not super successful. Luckily, I got lots of cuttings from my sympathetic neighbors. —Wendy Helfenbaum

Next, check out our favorite secrets from the garden center.

Emily Hannemann
Emily Hannemann is an associate digital editor for Birds & Blooms. She has a bachelor’s degree in English and a master’s degree in magazine writing from the University of Missouri - Columbia. When she’s not writing and editing, you’ll find her swimming, running, or hiking. She knows blue jays are controversial, but she loves them anyway.