You’d expect an avid gardener to have a lovely garden, full of healthy, well-cared for plants, arranged in pleasing combinations. And yes, most are a delight to the senses. However, even the most dedicated gardener can make mistakes. Here are three foibles common to many a crazy plant person. Can you relate to any of these?

Crazy Plant Person Mistake #1: The Plant Collector.

I admit—I struggle with this one. There are so many wonderful, beautiful, fascinating plants out there that I want to own them all. Combine that impulse with a relatively small yard, and the only way to fit everything in is to buy one of each. That appears to be what these homeowners have done. The yard is clearly a labor of love, but when I saw it, I also felt somehow… agitated.

The problem is, just as a room filled with a random collection of furniture in a rainbow of colors seems cluttered and leaves us feeling unsettled, a landscape filled with one-of-a-kind plants is neither tranquil nor relaxing.

It’s fine to include a plant that acts as a focal point—a weeping cherry, a stand-out crabapple, a sculpted topiary, or (below) a red-leafed Japanese maple—but the plants in the yard shouldn’t be competing for our attention.

No matter how lovely a particular plant is, our brain knows that nature tends to clump similar plants in groups. So, instead of a variety of solo performers, include repeating elements—using the same species in more than one part of the yard.

The time to act is at the garden center. Purchase more than one or each type of plant. Of course, how many depends on how large the plants get and how big a space is allotted for them. Three would be a minimum, and often five look even better. For some reason, odd numbers appear more pleasing to the eye. Yes, you’ll have room for fewer types of plants, but having a cohesive landscape is worth some self-restraint. The rest will just have to be appreciated in someone else’s garden.

(The opposite extreme is also an all-too-common mistake—having an entire yard comprised of just grass and junipers, for example—but that’s rarely an issue among crazy plant people.)

Next week I’ll address two other mistakes common to crazy plant people—like me.