A lesson in the meaning of plant growth types, as seen on my individual herb plant listings…
These are the herbs in your garden that have leaves all year round and have woody stems. They tend to have multiple stems and expand sideways through natural layering. They are there for all seasons but naturally slow their growth down during winter.
Examples of woody perennials are White Sage, Rosemary, Common Sage, Southernwood. Also Thyme, Hyssop and many others…
Perennial Crown Herbs
Perennial crown herbs have a “crown” of growth at ground level that may divide and sloowly expand. Most of the perennial crown herbs go dormant in winter, dying back to the crown and come back up smiling in spring. Garlic is in this group and the only one that will show its face in winter (try leaving just one clove in the ground instead of harvesting it in summer, you’ll eventually get a patch of garlic greens).
Other herbs as an example; Chives, Figwort, Echinacea, Lady’s Mantle, Lovage, Wormwood. Sometimes pays to put a marker where they grow so you don’t accidently dig them up in early spring!
Sneaky bunch are the spreading herbs… One minute they’re in one place next minute you spot their progeny up to 5 metres away (Horsetail and Passionflower looking at you)! Still connected to the mother plant!! What the whaaa!?
You gotta love them for their tenacity. What they have that others don’t, are runners. Underground roots that you may as well call stems as they all give rise to new plants. Most of these plants are dormant in winter so you don’t realise what mischief they’ve been up to ’til spring..
To control, most people grow these plants in containers and I recommend this practise… Even if I don’t practise it myself!
Example of spreading herbs are of course, the Mints, Tansy, Soapwort, Yarrow, Liquorice..
Expanding Clump Herbs
Expanding clump herbs are like spreading herbs (see above) but at a much slower rate, hence they create for themselves a dense clump that gets bigger each year. And they usually don’t surprise you by popping up somewhere un-expected but still connected.
They do most of their regeneration at or below ground level and you need to cut them back fairly hard to stimulate them to grow new shoots. So when harvesting or pruning, go right to the bottom of the plant, no tip picking!
Example of herbs; Lemon Balm, French Tarragon, Bergamot, Oregano, Comfrey, Dandelion.
Annuals, Biennials, Short-lived Perennials
An annual is a plant that will flower, go to seed (or fruit, like tomato) and die in their first season, though some will live onto their second year. Life cycles range from 3 – 15 months. Basil, German Chamomile, Calendula and Honesty are some examples.
Biennials normally don’t flower until their second year, then they’ll set seeds and die. Sometimes they’ll hang out a bit longer, sometimes shorter if there’s been a cold spell. Examples are Clary Sage, Teasel, Curly-leaf Parsley.
Short-lived perennials are plants that can live up to 2-5 years but have really done their dash after two and are best treated as annuals. Catnip is an example.
Lines can be blurred with these three growth types as depending on your climate things can be different. Plants that are usually perennial in their native setting are treated as annuals in less than ideal places. Clary sage always flowers in its first year for me because we’re in a cool climate (Eketāhuna) but the plant still lasts more or less two years. So yeah, a little bit of a curly one to set in stone, particularly between biennials and short-lived perennials.
Trees and Shrubs
Hopefully this one is pretty self explanatory but just to cover the basics ‘Tree and Shrub’ herbs are just like woody perennials but will form a trunk and branches and grow somewhat larger, ranging from 2 to 60 metres tall and will live for longer. Some are deciduous, meaning they lose their leaves in Autumn/Winter, examples are Elder, Hawthorn and Lemon Verbena. Some are evergreen, meaning they will always have leaves, Bay being an example.
I hoped this has helped clear up some botanical terms that you’ve always scratched your head at. Or that you’ve learnt at least one new thing (garlic is not an annual!).