In the garden: Terminology is an annual problem and a perennial challenge
This is a good time of year for a short refresher on a couple of simple, but often confusing gardening terms.
These things should be straightforward, but words can be interpreted differently when used in a context outside gardening. For example, festivals, birthdays and the Stanley Cup are annual events; they happen every year (except for the Leafs). Someone new to gardening might then be forgiven for assuming that an annual plant is one that’s going to show up in the garden every year.
Annual plants, also referred to as bedding plants, complete their life cycle in one growing season. Between spring and fall, the seed germinates, the plant grows, flowers, sets new seed, and then dies completely — leaves, stems and roots. Except, depending on the specific plant and if the conditions are right, the seeds might survive winter and sprout in spring. It’s still an annual plant, but when it appears in the same patch every year, isn’t it then a perennial? No, but it might look that way to a casual observer.
A perennial plant, and this includes trees and shrubs, is a plant that lives for at least two years and possibly even for decades. That might sound like a better deal than annuals, but not if you want to have plants that flower all season long, as most annuals do.
Garden perennials typically flower for a much shorter period than annuals do, although there are exceptions. Perennials sprout up in spring, then rapidly push out foliage followed by short lived, seed producing flowers. During this period and until the plant dies back in fall, energy is being stored in the roots, bulbs, tubers, or rhizomes below ground where the buds are set for growth the following spring.
In horticultural terms, these plants that die back to the ground in fall are referred to as herbaceous perennials. Familiar examples are day lilies and hostas. Plants that have hard stems and survive winter above ground are called woody perennials and these include trees, shrubs and vines. An odd one is the hellebore. It stores its food in a rhizome below ground, but it has biennial, almost woody stems that are evergreen.
This is where I confess to planting many perennials that behaved like annuals by dying completely after one season — but that’s the gardener’s fault; it’s still a perennial.
To add to the confusion, annuals and perennials are found within the same species. Some plants, such as Black-eyed Susan, will behave as either a perennial or an annual depending on where they are grown. A long growing season will allow a Black-eyed Susan to produce lots of seed, but if the season is short, it will play safe and live on as a perennial.
And then there are the biennials (or biannual). What’s that, you say — something that flowers once every two years or twice a year? Afraid not.
A biennial plant takes two seasons to complete its lifecycle. The seed sprouts, grows leaves, stems and roots during the growing season, typically forming a rosette of leaves at ground level with a short stem, but no flowers (exceptions coming). It then goes dormant over winter.
The following spring or summer, it grows new stems and seed-producing flowers, hangs around until fall and expires. Two years and it’s all over for the biennial, but new plants grow from the fallen seed.
Common biennials are fox gloves and hollyhocks, except that different species in the genus are short-lived perennials and to further bamboozle the gardener, breeders have hybridized biennials that flower in the first season.
And if you’re wondering why your lovely annuals that flowers all summer long don’t seed themselves everywhere, it’s because many new hybrids are grown from cuttings and don’t produce viable seed. Then there are tropical perennials like canna lilies that we grow as annuals.
Confused yet? Just keep on planting.
