Garden Jargon Made Simple

Simple definitions for common gardening terms.

Habit: "A plant's habit is its direction of growth," states Wallace Pill, Ph.D., professor of horticulture at the University of Delaware. "A plant that grows straight up has an 'upright' habit and one that grows along the ground has a 'prostrate' habit. The many variations in between don't have specific names, so the habits of those plants are described in lots of different ways." 
Hardy: In most parts of North America, a key question to ask about any perennial plant is "Is it hardy in my climate," which means "Will it survive winter where I live?" In fact, the continent is divided up by the U.S. Department of Agriculture into "hardiness zones" that help cue gardeners to know which plants will survive winter in their climate. Labels accompanying plants sold at nurseries often denote how hardy a plant is: either by zone ("Hardy through zone 6") or by temperature ("Hardy to -26 degrees F"). 
"A plant that is said to be half-hardy for a particular area is one that will survive most winters, but cannot take the worst winters in that region," explains Wallace Pill, Ph.D., professor of horticulture at the University of Delaware. "If you decide to try growing a half-hardy plant, you'll give it its best chance for survival if you put it in a south-facing site near the house or another windbreak that will give it some protection from the elements." 
Heeling in: You get a new tree, shrub, etc., but the place where you want to plant it isn't ready for you to put it in the ground yet. How can you keep the tree (or whatever) healthy until you can plant it? Heel it in! "Just dig out a couple shovelfuls of loose soil in a shady place and put the plant's rootball in the soil and then cover it lightly," explains Sam Benowitz, proprietor of Raintree Nursery in Morton, Washington. "Water those roots occasionally and the plant can stay there for quite a while—weeks, even months. This is what most nurseries do with the plants before they sell them to you." 
Humus: This is a term that can mean two different—though similar—things, according to Wayne Honeycutt, Ph.D., a USDA soil scientist working at the University of Maine. "To some people, humus means any organic matter like leaves or wood chips," Dr. Honeycutt elaborates. "Other people use humus to mean organic matter that has decomposed to the degree that it is no longer distinguishable from the soil itself." The difference between those definitions becomes important when gardeners are advised to add humus to their soil—should you mix in fresh organic matter like chopped leaves or grass clippings or decomposed organic matter, better known as compost? "I believe that adding fresh material stimulates activity of the microbes in the soil and that has lots of beneficial effects for your plants and the soil," Dr. Honeycutt avers, "so mix in fresh organic matter when you plant." 
Hybrid: Many new varieties are created when plant breeders combine the characteristics of two different plants into a new one by taking the pollen from one plant and using it to pollinate the other, which in turn produces seeds for a new generation. The plants that grow from those "cross-pollinated" seeds are called "hybrids." 
"When the two parent plants have been bred for consistency—so that they will reliably have the same traits each time they're grown—the next generation are called 'F1 hybrids' and they are uniform, too," explains Dennis Stimart, Ph.D., a professor of plant genetics and physiology at the University of Wisconsin. "However, the seeds produced by the F1 hybrids will not grow into a next generation that is uniform—if you save the F1 hybrid's seeds and plant them, the F2 generation may have lots of undesirable traits." 
Inflorescence: For such a big word, inflorescence (in-FLOOR-es-sense) has a very simple meaning. It is the way to describe a flower that is made up of many flowers, like you see on hyacinths or hydrangeas. "You sometimes hear people using inflorescence more broadly to mean just 'flower,'" notes Gus De Hertogh, Ph.D., professor of horticulture at North Carolina State University, "but the specific definition of the multi-flowered blossom is more accurate."