Deciphering plant tags: annuals, perennials and biennials

Do you remember the first time you went to a garden center? All those colors. All those plants. All those fancy tags with gobbledygook. Help! Plant terminology can vex everyone, even plant geeks. So let me give you the lowdown on some terms that flummox newbies and pros alike.  

The first thing you need to know is that for plants, it’s all about sex. Their number one priority is to make more of themselves. So they are committed to growing robustly to make flowers and seeds. How they get there is different. So we use words like annual, perennial, and biennial. These often confuse folks. Which one do I want? How do they work? What’s the best deal?

It’s all about a plant’s life cycle. Annuals live for a year. Perennials live longer. And biennials take two years to complete their life cycle. Annuals are especially driven to produce seeds because they only have one year to do so. So they push out flowers like mad to make more seeds.

Tithonia – an annual flower. Photo by Marie Bikle.

Annuals’ key selling point: color throughout the growing season. That’s why they are the darlings of container gardens, a blessing for filling gaps and ideal for a sweep of long-lasting color.  

Annuals are less expensive since they last only one season, dying with the first frosts. You can save seeds and replant them, but few do. Some come back from dropped seeds, but that’s rare. 

The downside to annuals is the need to replant them every year. So the cost savings may not be there in the long run and you spend much more time planting. 

In gardens, geraniums, begonias, pansies, marigolds, zinnias, petunias, and snapdragons are commonly treated as annuals.

Perennials are one and done, planted once and persisting for years. Most die to the ground with cold weather, but come back again from their roots, bulbs, or tubers. Most perennials bloom for about a month, but some bloom 2 or 3 times a season if deadheaded. So you don’t get the long flowering time of annuals, but they return year after year.

Perennials cost more but don’t need to be replanted. Plus, they give a different look to your garden throughout the growing season with myriad colors and forms. Perennial gardens have spring, summer, and fall wardrobes. They also are the gift that keeps giving, since you get free plants by dividing perennials every few years. This mitigates their initial higher price tags.  

There are hundreds of perennials including coneflowers, lavender, coral bells, coreopsis, columbine, bee balm, phlox, asters, and goldenrod.  

Biennials flower in their second season. They push out leaves the first year, then flower, make seeds and die in their second year. Hollyhock, foxglove and Sweet William are common biennials. Some biennials reliably reseed so they act like perennials with new plants coming from dropped seeds. Hollyhocks are notorious for rewarding growers year after year.   

I hope I’ve simplified some plant tag terms and made it easier for you to pick what’s right for you – and your gardens – on your next visit to a garden center. 

By Annette Cormany, Principal Agent Associate and Master Gardener Coordinator, Washington County, University of Maryland Extension. This article was previously published by Herald-Mail Media. Read more by Annette.

This article was previously published by Herald-Mail Media.

Monthly Tips for April

galls on Virginia cedar

Outdoor Garden and Yard Tips

  • Cedar-apple rust disease forms its galls on Virginia cedar (Juniperus virginiana) in April. The odd-looking galls are at first bright orange gelatinous balls with long “horns” or projections; they later turn brown and become hard. They are the alternate host structure for a disease that does very little harm to the junipers but can be quite destructive to apple trees, hawthorns, and quince.
  • Continue planting and transplanting trees and shrubs.  Choose quality trees: shade trees should have a single, straight trunk. Planting and transplanting should be completed before the end of June.

    Eastern Box Turtle
    Eastern Box Turtle
  • Viburnum leaf beetle is a serious pest of native arrowhead viburnum, cranberry bush, and many others. Look for feeding damage on viburnum and yellow larvae. Control them promptly since they can defoliate plants. Repeated defoliation can result in the death of native viburnums.
  • Eastern box turtles and various species of snakes are coming out of hibernation and may visit your yard. Box turtles are becoming scarce through much of Maryland because of road mortality and habitat destruction. Observe it but leave it in the wild.

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Monthly Tips for March

Lawn

  • Late winter-early spring is considered the second-best time (the best time is late August through mid-October) to seed your lawn make repairs, or to cover bare areas. Read (PDF) HG 102, Lawn Establishment, Renovation and Overseeding.
  • Soil testing can be done now.  For grass keep the soil pH in the 6.0 – 7.0 range to help maintain, vigorously growing healthy turf. Although tall fescue is a little more forgiving of acidic soil, it will still grow much better at the proper pH. Not sure how to take a soil sample?

Ornamentals

  • If you still have unplanted bulbs from last fall, plant them this month. Inspect them carefully and only plant the best quality. Many may be in bad condition and not worth planting. If they were stored where it was warm, they likely will not flower this year but once getting established should do well next year.
  • Groundcovers are arriving in local nursery and garden centers this month. They are a great alternative to grass where grass won’t grow, where you have heavy shade or tree root problems and on steep slopes.
  • Remember not to set out tender annuals (impatiens, marigolds, petunias, salvia, etc) until after the last frost date. This date varies across the state from late April on the Lower Eastern Shore to Late May in Western Maryland. Refer to our Spring frost/freeze table.

Vegetables

  • Potatoes, onion sets, onion seedlings and peas can be planted as soon as the soil can be lightly worked. Chinese cabbage, leeks, beets, kale, mustard, and turnips can also be planted now. Learn more about these spring crops.
  • Buy some floating row cover material to protect crops from pests and promote early growth. A floating row cover is a lightweight spun fabric that permits light and water to enter, traps the soils natural heat and keeps out many pest insects.
  • Avoid the temptation to turn over or dig into wet soil. Tilling wet soil can cause it to become cloddy and brick hard when it dries out. How do you know when your soil can be turned or tilled? One test is to form a clump of your soil into a ball. Bounce it up and down in your hand a few times. If it breaks apart easily it’s probably OK to dig!

More tips from the Home & Garden Information Center

The Home & Garden Information Center’s horticulturists are available year-round to answer your plant and pest questions. In addition to gardening questions, we cover houseplants, indoor pests, and more. Send your questions and photos to Ask an Expert!

Monthly Tips for November

Ornamental Plants

  • pansiesPansies are a good choice for fall and winter color in the garden. If you want to plant pansies you need to do it very soon to assure that their roots get established for winter. As a bonus, pansies often overwinter and provide early spring beauty.
  • Spring flowering bulbs can still be planted. For best results, place them in a sunny spot in well-drained soil amended with compost. Fertilize the planting area with a balanced fertilizer containing nitrogen, phosphorous, and potassium. Bulbs can be protected from animal pests by surrounding them with a wire mesh like chicken wire. If deer or other wildlife have ravaged your past bulb plantings, try planting bulbs that are rarely damaged by deer, such as allium, narcissus, fritillaria, hyacinth, and scilla.

Vegetables

  • fallgreens1.closeup.Orazi_.'08.ppt_This is a good time to incorporate organic matter into your garden beds. Composted animal manure (horse, cow, sheep, chicken) is excellent for improving garden soil. Keep garden beds covered with shredded leaves to minimize the risk of soil erosion and nutrient run-off. These can be tilled into the garden in spring or left in place as a mulch between rows of vegetables.
  • Cover crops should be planted before Oct. 15 but increased soil and air temperatures, due to global warming, may allow early November sowing of winter wheat or winter rye.
  • Spinach, lettuce, arugula, kale, and other cool-season crops should be protected from freezing with a cold frame, plastic sheeting, or floating row cover. Be sure to vent your cold frame or plastic cover on sunny days to prevent excessive heat build-up.

Insectscamel_cricket_l

  • You may notice large, brown humpbacked crickets with long antennae that don’t chirp. These are camel or cave crickets (photo on right) and are attracted to damp, dark locations in the home, usually in the basement, the garage, or garden shed. Exclude them as you would other nuisance pests by sealing up openings around foundations, doors, and windows.
  • Stink bugsladybird beetlesboxelder bugshouse flieselm leaf beetles, and a few other critters may be observed in large numbers congregating inside your home. Cooler fall temperatures are driving them indoors. The ladybird beetles are actually beneficial insects that will not breed or survive for very long indoors. Simply vacuum or sweep up any unwelcome guests. The stinkbugs and the other invaders will do no harm indoors except to be a nuisance. Escort these invaders out of your home or vacuum them up, but resist the impulse to spray an insecticide. You can also prevent pests from coming into the house by caulking openings around window and door frames and not storing firewood inside the house.

More tips from the Home & Garden Information Center

The Home & Garden Information Center’s horticulturists are available year-round to answer your plant and pest questions. In addition to gardening questions, we cover houseplants, indoor pests, and more. Send your questions and photos to Ask an Expert!

Lawn and Garden Tips for March

Seeds

Ornamental Plants

  • Starting Seeds Indoors – Many types of annual flower plants can be started indoors this month. Generally, most are started 5-6 weeks before they are planted outdoors.
  • Spring bulbs are emerging and some are even flowering at this time. Exposed leaves may be burned later by very cold temperatures but the spring flower display will not be adversely affected.
  • Groundcovers are arriving in local nursery and garden centers this month. They are a great alternative to grass where grass won’t grow, where you have heavy shade or tree root problems and on steep slopes.

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Lawn and Garden Tips and Tricks for August

For Ornamental Plants:

  • Late August through September is usually a good time to transplant, divide and plant perennials such as daylily, liriope (photo left), and echinacea.  Be sure to keep them well watered during dry periods.
  • Annuals and perennials, like yarrow and salvia, may have grown spindly and are not flowering well. Cut them back to encourage re-bloom. Deadhead the spent blooms of annuals like zinnias and marigolds. This will encourage them to continue blooming more vigorously.
  • Plant hardy mums for fall color this month so they will become well established prior to the winter.

More August ornamental tips

For Lawns:

  • In dry periods grasses go dormant but recover when rain returns. Newly seeded or sodded lawns may actually be dead and will need to be reseeded.
  • Mid-August through mid-October is the best time to start new lawns and renovate or overseed existing lawns. We recommend a turf-type tall fescue cultivar at a rate of 4 lbs. of seed per 1,000 sq. ft. of area for overseeding, or 8 lbs. per 1000 sq. ft. for new lawns.
  • If your lawn area contains more than 50% weeds, consider a total lawn renovation. Newly seeded turf must be watered regularly. See Starting a New Lawn.

More August lawn tips

Outdoor Insects:

  • You may notice the European hornet stripping the bark off shrubs (especially lilac) and trees. This stripping of the bark is usually minor and does no real harm to a shrub or tree. The European hornet is a large yellow and brown hornet (photo) that nests in cavities in trees, stumps, wood piles, sheds, etc. and feeds on insects. Unlike most other wasps and hornets this one is a night flyer.
  • Do not spray pesticides in your garden unless you’ve observed a particularly serious pest and the damage caused by the pest. Follow all label directions. Always select the shortest residual, least toxic insecticide to avoid killing beneficial insects.
  • Avoid mosquito and midge problems by turning over any pots, lids or saucers that might collect water and create a breeding site. Also check clogged house gutters another favorite breeding place for mosquitoes and midges. Many people use corrugated drain pipe attached to downspouts to help move water away from their homes. The corrugations hold water and are a prime place for tiger mosquitoes to breed. To avoid the problem, use a smooth drain pipe or securely attach the corrugated drain pipe to the downspout and cover the open end with a piece of pantyhose secured with a rubber band. This will keep adult female mosquitoes and midges out of the drain pipe.

More August indoor and outdoor insect tips