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Spring is the right time to take cuttings from many of your favourite herbs and clone them into new plants.
When I say ‘clones’ the new plants will be genetically identical to their parent plants but you won’t have to go through all the science and expense that folks do in the lab. You won’t even need to wear w white coat (though they do look cool). As with many things, the plants do the work for you but a little scientific knowledge will help you out a lot.
During workshops and conversations, folks often ask me how to know which plant prefers which method of propagation? The secret is to learn the Families. Families are large groups of plants that are related through various common features.
Classifying plants is called ‘taxonomy’ and the parts of the lists that you see in textbooks that you need to concern yourself with are are Family, Genus and Species. The rest is pretty irrelevant to us in the home garden. You can tell the Family entry because it always ends in -eae, for example ‘Lamiaceae’. You may be familiar with genus and species from books and plant labels where you’ll see things like ‘Mentha spicata‘. Mentha is the genus and spicata is the species. Formally, the genus and the species are always written in italics e.g. Mentha spicata. Genus always starts with a capial letter and species never has one.
W-a-a-a-a-y back in the old days, plants were grouped by identifying distinguishing features of their flowers. The finer the differences, the closer the plants are related and further one works down the taxonomic tree from Family to genus to species and even to subspecies. That method held true for centuries and can still be used today in the field. Nowadays though, the details are all worked out by analysing microscopic detail and the plant’s genes. Some plants have been shifted in their classification due to advances in genetics and microscopy. For example, Rosemary, which used to be listed as ‘Rosmarinus officinalis‘ is now known to be closer to Sage and is called ‘Salvia rosmarinus‘. Luckily, they’re still in the same Family, Lamiaceae.
Further down the track, I’ll write a whole post on simplifying the essential botanic Latin and Greek that we, as home gardeners, need to know to make our jobs easier and to impress people at parties.
As we get further down the taxonomic list, and more to the right of the name, plants with similar names are increasingly closely related. This means that the plants sharing the same genus and species names can generally be propagated, grown and harvested in the same ways.
Generally, members of the same Family have similar needs and respond to the same gentle attentions of we home gardeners.
Don’t be concerned with the large number of Families either. So many of our food and medicinal plants are in the Families Lamiaceae and Solanaceae , so get to know them first and you’ll have most of your bases covered. Trees are a bit different and things like Corn and Wheat are grasses generally on the Family Graminaceae and that lot can be a bit confusing
One of the best plant Families to learn with is Lamiaceae, the Mints. Many of our usual garden herbs are in this huge Family – all of the varieties of Mint, Sage, Rosemary, Lavender.
The process of propagating many plants in thes Family is pretty straightforward. Take a cutting 10 -15 cm long
Strip off lower leaves and reduce the number of upper leaves by removing some or cutting some of the larger leaves in half. This helps reduce the amount of water lost from the plant through transpiration.
Optionally, dip cut area in honey. his helps stop any fungal infections from occuring while roots are forming.
Plant the cutting into damp potting mix or leave it in a jar of water, both work just as well. Roots will start to form after a few days to a couple of weeks depending on the plant variety and the temperature.
If you’re leaving the cuttings in water, you should change the water every week to stop algae growing in it.
Keep the cuttings in a warm place, with a bit of sun and in 4-6 weeks you’ll have a new plant ready for planting out
This technique also works for many other plants, especially Tomatoes (which aren’t Lamiaceae, but Solanacea).
You can add a little home made rooting hormone or a dash of a commercial one but Lamiaceae are pretty vigorous and don’t really need it.