Herbs can usually be pruned while harvesting for use. This is often enough to keep the plant healthy and bushy. However, if you are not getting around to using all of your herbs (especially if you have a lot of herbs), you may need to prune as well.
When to prune your herbs
Midmorning is the best time of day to prune herbs for adding to meals or for medicinal uses. The morning dew has dried, and the herbs have not yet been exposed to the heat of the day. This will help to retain the scent and colour of the herbs.
A sunny day is preferable for pruning herbs; the morning sun enlivens the herbs with its energy, activating the aromatic oils within the plant.
Rain can make plants excessively wet, and some leaves retain a lot of moisture. This can lead to damage when overhandling, and the herbs may lose their aroma.
Avoid pruning in the middle or afternoon of a hot day, as the leaves and flowers will be beginning to fade.
When picking herbs for a salad it is best to pick them in the morning as later in the day they may be wilted from the hot sun.
How to prune your herbs?
Plants grow upwards and outwards because growth hormones concentrate at the ends of the growing shoots, suppressing the development of buds elsewhere. Cutting off (pruning) a growing tip redirects the plant’s energies to lower buds and stimulates them into growth as replacements for the lost leading shoot. This leads to bushier plants and prevents them from becoming woody and or sparse.
General Pruning Tips
Always use clean, sharp scissors, trimmers or secateurs. This helps to make clean cuts, prevent damage to the plants and reduces the risk of disease.
As a general rule, never remove more than one-third of the plant at a time. Taking too much can stress the plant.
Plants require some leaves on their stems to photosynthesize and create new growth. Always make sure to leave some green growth.
Once some herbs are past their best, often after flowering, it is a good idea to give them a hard cutback to encourage fresh growth and give the plant a better shape.
Perennial herbs will generally need a hard cutback once a year.
Cutting back Bushy Herbs that produce their leaves on Stems
These include but are not limited to:
Amaranth
Basil family
Bay tree
Catnip
Chillies
Curry plant
Damiana
Jasmine sambac
Lavender family
Lemon Balm
Lemon Verbena
Mint family
Mugwort
Mushroom plant
Rosemary
Sage
Saltbush
Salvias
Sambung
Scented geraniums
Shiso/perilla
When picking these herbs, never rip leaves from the plant. Instead, cut the stem back to above a leaf node with signs of life, and the plant will then bush out from this area.
Then, you can remove the leaves from the stem that you have cut off and use them in your meals.
Note: Handle the cut herb as little as possible, to avoid bruising, particularly with the more succulent herbs, such as basil.
Avoid cutting back into brown hard stems as your herb may not recover it is preferable to prune lightly and regularly to keep your herbs looking fresh and bushy.
Cutting back small-leaved herbs that produce their leaves close together on stems
These include but are not limited to:
Brahmi
Chamomile lawn
Marjoram
Moneywort
Oregano Family
Thyme family
Rupturwort
Savoury family
Speedwell
Smaller leaved herbs can be cut in one motion across a large portion of the plant a bit like giving it a haircut. There is not so much concern for finding the nodes as there are many along the stem.
Note: You can mow a thyme lawn or a chamomile lawn to remove some of the top foliage and limit upward growth and encourage bushy side shoots.
Herbs that grow in a rosette produce new growth from the centre of the plant. These include but are not limited to:
Aloe
Angelica
Asian greens
Chervil
Chicory family
Comfrey
Coriander
Dandelion
Dill
Fennel
Lovage
Parsley
Salad burnet
Sorrel
Upland cress
Note: Take care when pulling the stems off fine herbs like dill and chervil you may want to use scissors to cut these ones or pinch them off with your fingernails.
The leaves come up from the ground like tufts of grass. These include but are not limited to:
Cat grass
Chives
Lemon grass
Society garlic
Vanilla grass
Vetiver grass
I hope you enjoyed that information about pruning. Pruning and harvesting at the right time and in the right way can significantly enhance your herb garden’s productivity and the quality of the herbs you grow.
Last year my partner saw my mother (a gardener) giving a hard prune to some of the hydrangeas. I’m not a pruning expert, but apparently this variety of hydrangea benefits most from a really hard cut at a certain point in the year.
My partner, all good intentions, took our citronella and cut it in the same way - right down to a nub. Needless to say it died almost immediately
Rest peacefully, little citronella
Anyways, what I’m trying to get at is that pruning can be tough and varies a lot by the type of plant - having a handy list and gathered resources like this is super helpful! I ought to do some studying too!
Thank you very much for this handy guide, @starborn!
My great-grandfather used to spend most of his weekend in the garden. He would take breaks to eat oranges, and I would join him when I visited.
The amount of time, care, and effort that goes into maintaining a garden of plants never ceases to blow my mind. While it’s not my thing, I can definitely appreciate the joy in giving something the conditions in which it can grow and thrive.
Yup! The very definition of “learning things the hard way”
That’s such a nice memory of you and your great-grandfather
Thank you for sharing both your appreciation and wisdom with us - gardening is a very labor-intensive and often tricky endeavor, but it does bring beauty we can all enjoy!
Note: Handle the cut herb as little as possible, to avoid bruising, particularly with the more succulent herbs, such as basil.
Thank you! 
