Perennials vs․ Annuals: What’s the Real Difference and Which Should You Plant?
Perennials live three or more years‚ dying back in the winter and coming up from the same root system in the spring․ Annuals only last for one growing season․ They go through a four stage life cycle (germination‚ flowering‚ seed production and death) therefore needing to be planted every year․ That’s about it‚ but which of these to plant (or how to combine both) depends on your budget‚ how much yard work you’re willing to do‚ and‚ to a certain extent‚ what part of the garden you’re filling․
Almost all of the state is within USDA Hardiness Zones 6b through 7b․ The southernmost and southeasternmost parts of the coldest part of Appalachia are in hardiness zone 6a․ This is important when choosing perennial plants‚ as a perennial that comes back year after year in Memphis may not survive the winter in Bristol or Gatlinburg․ Knowing your zone before you buy will save you money and frustration․
Perennials: The Long-Term Investment
Perennials survive winter dormancy to flower again in the spring because they store energy in the root system (rhizomes‚ tubers‚ or fibrous root systems)‚ and do not need to be replanted each year‚ but instead often take one or two years to become established․ For gardeners‚ this is called the ““sleep‚ creep‚ leap”” pattern: in the first year the plant is settling into its new location and not putting on a lot of growth‚ in the second year there is noticeably more growth․ In the third year the plant is at its largest size and in bloom․
In fall‚ when you plant Daylilies or Hostas in Tennessee‚ you don’t expect them to look beautiful the following spring․ You’re building something that’s going to be here in ten years with no upkeep․
There are a few things perennials shine at in Southeast gardens:
* Coneflowers (Echinacea) and Black Eyed Susans (Rudbeckia)‚ which are most resistant to the humid summer weather and clay soil of Tennessee‚ bloom regularly all summer (June through September) and attract pollinators․ * Sedum does well in the well-drained‚ rocky areas in which other plants sulk and is practically drought-proof once established․ * Peonies require a true winter chill to bloom well‚ making them suitable for Middle and East Tennessee‚ but often disappointing in the west‚ where milder winters limit flowering․ * Bee Balm spreads underground through rhizomes‚ and can fill a bed within two or three seasons․ This can be helpful if you do not want to buy dozens of plants․
Perennial root systems also provide important services below ground․ Plants such as coneflower and iris can break up compacted clay soil (an active problem in Middle Tennessee) and hold soil in place on slopes‚ which is useful when gardening along a creek bank‚ or on a graded yard․
The tradeoff is that most perennials bloom for only two to six weeks before they become mostly green for the rest of the year․ That’s why experienced gardeners usually plant many different kinds of perennials with different bloom times‚ such as early Iris‚ summer Coneflowers‚ and fall Sedum‚ so something is always in bloom․
Annuals: Quick‚ Fertile and full of color
Annuals skip the two- or three-year establishment process entirely․ They are bred to grow quickly and flower in one year‚ then die in the first frost․ That makes them the right choice when you need an instant burst of color‚ in hanging baskets‚ in a new bed you have only the loosest outline of‚ or on a porch in a container that has to look finished right now․
In Tennessee‚ most annuals are planted outside after the last frost date‚ which ranges from early April in West Tennessee to early May at higher elevations in East Tennessee․ Blooming starts 4 - 8 weeks after planting‚ depending on the plant․ The workhorses are the petunias‚ zinnias and marigolds‚ tolerant of heat and humidity and still looking good by July․ This can’t be said for many annuals that do well in the cooler months‚ for example pansies (which are a fall-through-spring annual in this area‚ as opposed to a summer plant which they are not at all‚ and actually sag under summer’s heat)․
The flip side to that instant gratification is the work involved in maintaining annuals․ They require regular (even daily in July and August) watering‚ deadheading‚ and annual planting․ If you go away for a week in the summer and don’t set up some kind of irrigation system‚ you shouldn’t be too surprised to find a dry‚ wilting bed․
Which One Actually Makes Sense for Your Garden?
Neither is better‚ they are just different․ A garden bed that looks good with less work five years from now is a better dollar-for-dollar value if it is planted with perennials․ Once you have a planting of Daylilies or Hostas‚ you can divide them every few years into three or four separate plants‚ eliminating the need to buy them again․
If you want color this season‚ test a new design without waiting for perennials to fill in‚ or need something to fill in around young perennials‚ annuals do the trick․ In Tennessee‚ many use a perennial mix of Coneflowers‚ Hostas‚ Sedum and the like to build the structure of their garden‚ and plug in spots of annuals around the edges or in pots․
One thing worth mentioning that a lot of general gardening guides skip: not every ““perennial”” behaves the same way in every climate․ Some plants sold as perennials in northern catalogs are grown as annuals in the Deep South because they don’t survive our winters‚ and the reverse is true too – plants that die back completely up north can stay semi-evergreen through a mild Tennessee winter․ A good example is lavender․ Here‚ it is a true perennial‚ but because our heavy clay soil sits wet through the winter‚ raised beds or amended soil tip the balance in its favor․
We grow perennials well suited for our area‚ such as Daylilies‚ Hostas‚ Coneflowers‚ Sedum and hundreds more‚ so you’ll be working with plants already acclimated to our clay soil and humidity and not bred for a different region entirely․ This is more important than many gardeners know‚ because the plants you select will readily establish and survive the first Tennessee winter more readily than those which are not suited for the region․
Whatever the direction you go in‚ the true skill is to know which plant solves which problem‚ and what the question is in your particular yard․
