Annuals vs. Perennials: What Is the Difference?
Annuals live one season and flower for a long stretch; perennials return for years with a shorter show. Here is what the labels mean, why they change with climate, and how to use both in one bed.
Nursery benches are sorted into two big groups, and the choice between them shapes what your bed costs, how long it flowers and how much replanting you do. The annuals vs. perennials question is simpler than it looks, with one catch that trips up many new gardeners: the labels depend on climate.
Once you understand the difference, plant tags become much easier to read, and you can decide what to buy based on what you want the bed to do.
What is an annual?
An annual completes its whole life in one growing season. It sprouts, flowers, sets seed and dies, and you plant again the next year. For a short summary of how annuals grow and how they are used, see University of Maryland Extension.
Because an annual has only one season in which to make seed, it tends to flower for a long stretch, often for months if conditions suit it. That is why annuals are the usual choice for steady color.
Annuals fall into two broad camps. Warm-season annuals such as zinnias, marigolds and cosmos are frost tender and want warm soil. Cool-season annuals such as pansies, snapdragons and sweet alyssum prefer cool weather, tolerate light frost, and often fade in summer heat. Which camp does best, and when, depends on your climate.
What is a perennial?
A perennial lives for several years. Most garden perennials are herbaceous: the top growth dies back in the cold or dry season, and new shoots rise from the crown and roots when conditions improve. Coneflowers, daylilies and hostas are familiar examples.
The trade-off is bloom time. A typical perennial flowers for a few weeks each year, and is a mound of leaves for the remainder. Some bloom longer or repeat, and the timing and length vary with variety and climate.
Perennial does not mean permanent. Some kinds live for decades, others fade after a few years, and many need dividing now and then to stay vigorous. Most also take two or three seasons to reach full size.
And biennials?
Biennials take two years. In the first they grow leaves, usually in a low rosette. In the second they flower, set seed and die. Foxgloves, hollyhocks and sweet William are commonly grown this way.
Many biennials drop seed freely, so new plants keep appearing and the patch seems perennial. If you want flowers every year, sow or plant them two years running to get the cycle going.
The catch: the labels depend on climate
Whether a plant behaves as an annual or a perennial is not fixed. It depends on where it is growing.
Many flowers sold as annuals are really tender perennials: plants that live for years in frost-free regions but are killed by freezing winters. Geraniums (pelargoniums), lantana and petunias are common examples. Where winters are cold they are sold and grown as annuals; in a mild-winter region the same plant may carry on from year to year.
The reverse happens too. A perennial that comes back reliably in a cold-winter region may struggle where summers are very hot and humid, or where winters are too mild to give it the cold rest it needs.
So read the hardiness range on the tag and compare it with your own zone. If a tag says roughly zones 5 to 9 and you garden in zone 4, treat the plant as an annual or as a gamble. Ranges are approximate and differ between varieties, so check the tag of the specific plant in your hand. The guide to plant hardiness zones explains how to find your zone and what the numbers do and do not tell you.
Good to know
Zone numbers on most tags refer to the USDA system used in the United States. If you garden elsewhere, your country has its own hardiness map or rating system, and local nurseries will label plants accordingly.
Annuals and perennials side by side
| Feature | Annuals | Perennials |
|---|---|---|
| Lifespan | One growing season | Several years or more, where hardy |
| Bloom period | Long, often for much of the season | Usually a few weeks a year; some repeat |
| Cost over time | Low per plant, but bought or sown again each year | Higher per plant, spread over many years; clumps can be divided |
| Effort | Replanting each year, plus regular watering and deadheading | Less planting; occasional dividing, cutting back and staking |
| Best use | Season-long color, containers, filling gaps, trying new looks | The lasting framework of a bed |
Why most beds mix both
A bed of perennials alone has quiet spells between flushes of bloom. A bed of annuals alone starts from bare soil every year. Together they cover each other’s weak points.
A common approach is to let perennials form the framework: repeated clumps that return each year and give the bed its shape. Annuals then weave between and in front of them, supplying color while the perennials are out of flower.
Annuals are especially useful in a young bed. Perennials planted at their proper spacing leave bare ground for the first couple of years, and annuals fill it without crowding the permanent plants for long.
For plants to start with, see the lists of easy annual flowers for beginners and dependable perennial flowers for beginners.
Self-seeding annuals
Some annuals blur the line by sowing themselves. Cosmos, sweet alyssum, larkspur and cleome often drop seed that sprouts the following year, so they seem to return like perennials. In fact these are new plants.
Self-seeding is not something to count on. It depends on your winters, on how thickly you mulch and on how thoroughly you deadhead, since removing spent flowers removes the seed. Seedlings of hybrid varieties may also differ from their parents in color or height.
If you want volunteers, leave some late flowers to ripen, keep mulch thin in that area, and learn what the seedlings look like so you do not weed them out. If you do not, deadhead before seed forms and pull strays while they are small.
Which should you buy?
- For color this season, in a new bed or in pots, lean on annuals suited to the current weather.
- For a bed that builds year after year, choose perennials whose hardiness range includes your zone and whose light needs match the site.
- If you rent, or like to change the look each year, annuals keep you flexible.
- If unsure, plant a few perennials as anchors and fill around them with annuals. You can shift the balance as you learn what does well in your garden.
Frequently asked questions
Do perennials come back every year?
Only where they are hardy. A perennial returns from its roots if your winters and summers fall within the range it tolerates, so compare the hardiness range on the tag with your own zone. Even then, some kinds are naturally short-lived and fade after a few years, while others last for decades.
Why is a plant sold as an annual here but called a perennial elsewhere?
It is probably a tender perennial. Plants such as geraniums and lantana live for years in frost-free regions but are killed by freezing weather, so nurseries in cold-winter areas sell them for one season. The plant is the same; the climate decides how it behaves.
Is it better to plant annuals or perennials?
Most gardens use both. Annuals give long-running color in the first season and fill gaps, but need replanting each year. Perennials cost more at first and flower for a shorter time, but return and spread where they are hardy. A mix gives structure and steady color together.
