If you’ve ever found yourself in a garden center aisle looking at two seemingly unrelated plant, a giant sunflower on one end of the spectrum and a humble lettuce leaf on the other, you’ve likely marveled at how they look nothing alike, yet share a surprisingly similar genetic heritage. A quick glance shows you their connection, though: If you’re savvy to botanical family trees, clues jump off the page. This is all the more reason for chefs and backyard gardeners alike to get clued in about importance of plant families: Understanding which ones belongs together helps eliminate the guessing game when it comes to growing things.
In fact, their similarities are explained by their botanical origins different than how we eat them. These shared origins also determine everything from when to pick them to what kind of soil they need to grow in. Here is a breakdown of those eight primary families and how their common characteristics explain everything.
Why Plant Families Matter for Gardeners
The same holds true for all those members of the nightshade family, for example: Eggplant? Check. Potatoes? Check. Peppers? Check. And tomatoes? Check. All nightshades. In fact, they have five joined petals. Most also contain naturaly occurring chemicals called alkaloids. These aren’t necessarily poisonous, but they can be bitter-tasting and are certainly not good to eat raw.
It makes sense that they’d have much the same care requirements, why bother watering one more than the other when you know they’re cousins? All nightshades love steady moisture and prefers hot days in summertime. That’s what most gardeners tend to forget about plants that appear so different from each other. Why would you feed a tomato similarly to an eggplant? If the former is drooping around, it gets pity waterings, but not the neighboring pepper plant. Wrong.
Because we think of them as separate veggies, you’d think of them that way, right? As plants, though, they are close cousins who ask for basically the same treatment. That’s where humans fail at gardening: We assume things that look different is unrelated. Related plants treated as unrelated account for half the home-garden failures.
And then of course there are the legumes: lentils, peas, beans. Here’s the thing with these guys that many gardeners forget until it’s too late. When you grow legume seeds, whether they’re peas or beans, you’re not just creating a meal for yourself. Because plants and nitrogen-fixing bacteria in their root nodules works together, you’re also turning air into plant food. That’s right: You’re fertilizing the soil for future crops.
You can see the environmental advantage clearly from the chart. You’re not just picking up some beans to eat. You’re running a free fertilizer business for the whole area where you grow things. If you rotate the legumes (which need less food) with heavy feeders such as brassicas or corn, you’ll keep the ground rich, no man-made inputs required.
At one extreme, there are plants like cucurbits (melons, squash, cucumbers), which is sprawling vines that appear to spread in every direction and take over anything within reach. Their flowers differ from those of nightshades; many kinds also has separate male and female blooms on the same plant (a condition called having both sexes on one plant). The reason? That’s how you get fruit. Without any bees around to cross-pollinate between those giant blooms, no watermelon or zucchini for you.
Knowing how these flowers work can show why your crop may be empty. Not everything is caused by lack of sun or water. Sometimes it’s just because nothing pollinated during the short time the flowers bloomed.
What about other interesting cases? Take the mustard family, for instance. All crucifers (broccoli, kale, cabbage) is actually cruciferous plants, which means that each has four petals in a cross formation. And as you might guess from their biology, they are cool-loving plants. When heat comes around, these guys tend to get going to seed (or “bolt”). Why not plant them where their nature suits them, then; in spring and fall? Forcing kale (or broccoli!) in mid-July is futile; you’ll get bits of bitterness in your leaves and no heads to show for it. Fight it, and you lose. Work with it…and win.
Finally, there is the Rose Family. How many times have you seen roses, apples, strawberries, cherries…with lots of stamens and five petals? That’s how consistent their family is, and a good ID clue. Knowing it’s in the rose family, you can expect some special care like perhaps a certain soil pH (or even chill hours) for happiness. Knowing the family means knowing what their “hidden” needs might be, before they get too out-of-whack. You should of known that. The more you know, the more proactive you can be as a gardener.
That’s what happens when you go beyond focusing on each plant in isolation and find the patterns; when you realize that like flowers likes likes. When you figure out which crops leave the soil richer or poorer. You transform from a gardener who fixes things after they happen to one who plans ahead. It happens the moment you reach for another seed packet and look at the family name first. That little piece of botany knowledge will make you a better grower, a grower with a well-planned system rather than a chaotic patch of dirt, and not just around but with the plants themselves.