Do you know what happens to the majority of herb gardens within their first year? They either die off, grow wildly out of control, or manage to do a little bit of both. Why does this happen? It happens because, unless you know how to prune herbs, all of the careful planning and planting in the world will not be enough to maintain a healthy, productive, herb garden.
If you want to nurture a lush, vibrant, fruitful herb garden, you need to know how to prune.
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The Difference Between Pruning, Trimming, And Harvesting Herbs
You will often hear gardeners use the words “trimming,” “pruning,” and “harvesting” interchangeability. There are, however, three different techniques, with three different applications.
I’ve previously discussed the difference between pruning and trimming, but here’s the “lite” version:
“Pruning is when you make a single, precise cut, one stem at a time to promote the health and/or growth of a plant. Trimming is when you clip multiple stems at once in order to maintain the plants’ shape. Generally, less precision is required with trimming than with pruning.”
Now, to throw another term into the mix. Harvesting.
While similar to pruning, harvesting is subtly different. Harvesting requires the gentleness and precision of pruning. It would be easy to undo all of your hard work by harvesting too much of your herbs at once and causing it damage.
On the other hand, unlike pruning, when you harvest part or all of a plant, you are doing so in order to eat it and not to encourage growth. For this reason, you will be harvesting when the herb is at its peak flavor or scent and not when it is dormant or when you want to encourage growth and good health.
This a guide to pruning in order to maintain the health of your delicious plantings but I will also talk about the best way to harvest, use, and store your herbs.
Why Should You Prune Your Herbs?
The primary reason to prune any plant is to maintain good health. However, depending on the plant in question, pruning may also:
- Stimulate new growth.
- Prevent a plant from becoming top-heavy or tall and spindly.
- Encourage thicker bushier foliage.
- Promote the growth of more fruits.
- Direct the plants’ energy to the gardener’s preferred feature (fruits, flowers, foliage, etc)
- Propagate new root growth.
- Prevent the plant from growing beyond the space available for it.
How Much Should You Prune Your Herbs?
The goal of pruning your herbs is to encourage healthy growth. However, just as a little pruning can be a good thing, it doesn’t mean that a lot of pruning is better. In fact, quite the opposite is true. By over-pruning, you can impair your herbs’ ability to produce that rich tasty new growth you are looking forward too. In fact, by wielding the pruning shears over vigorously you might even kill your herbs off entirely.
So. How do you walk the delicate tightrope between light pruning, hard pruning, and pruning your herbs to death?
You find out what type of plants you have in your herb garden, that’s how.
Ways In Which Herbs Can Be Classified
There are many classifications for plants. Some of them are straightforward and some of them are a subject for debate. It would be easy to become bogged down in a discussion about the details and intricacies of classifications, but that’s not what we’re here for. In this article at least.
So. Below are definitions for some of the terms used in plant classification. These are seen, generally, as acceptable definitions and they may or may not be open for debate in the wider horticultural community.
Classification According to Tissue Type
Herbaceous
An herbaceous plant is one whose above-ground structures do not become woody. In addition, these structures die back at the end of the growing season. Technically speaking, all plants begin their lives as herbaceous plants. Some remain herbaceous while others go on to become Woody.
In a botanical sense, all herbaceous plants can be referred to as herbs. This can be confusing for new gardeners because when we speak about “herbs” in a herb garden we are referring to those plants which have a culinary, therapeutic, or another similar purpose.
In this guide, when I talk about herbs I am using it in the culinary etc. sense.
Woody
Some plants go on to produce wood as their structural tissue. These plants are woody but are not exclusively trees.
Classification According To Lifespan
Annual
A plant whose entire growing cycle is completed within one year. After this single cycle, the plant dies.
Biennial
A biennial plant takes two years to complete its lifecycle. During the first year, the plant produces roots, stems, and leaves before entering a dormant period over the colder months. Then, during the second year, the plant produces flowers, fruits, and/or seeds and then dies.
Herbaceous Perennial
These are non-woody plants that live for two or more years, with the plant dying back to ground level during the cold months. This is followed by new shoot growth in the spring.
Woody Perennial
Plants that live for two or more years, maintain a shoot system above the ground over the colder months and develop a woody structural tissue.
Classification According To Leaf Duration
Evergreen
Plants that retain their foliage year-round.
Deciduous
Plants that drop their foliage after the growing season.
Marcescent
Plants that retain dead leaves or petals.
These are just a few of the many, many ways in which plants are classified. However, this is all the terminology we need in order to discuss how to prune your herbs.
Herbs Which Require Light Pruning
Light pruning is most appropriate for the more delicate herbaceous plants in your herb garden. These are herbs such as basil, cilantro, and lemon balm. These herbs will flourish throughout the summer and depending on their life-cycle, either die back or die completely once the cold weather arrives.
Lightly pruning these herbs throughout the summer months will encourage them to sprout new growth, become bushier, and be generally healthier and more productive.
The best technique for these plants is “Tipping” which will encourage them to branch out and produce new stems. I’ll discuss tipping in more detail under techniques, but, basically speaking, tipping is cutting off the uppermost inch or two of growth in such a way that it encourages growth in two directions from the cut.
Herbs Which Can Cope With Hard Pruning
Woody herbs and some of the hardier herbaceous plants will survive, and in fact, may require some hard pruning.
These plants include thyme, sage, and rosemary, as well as a favorite both in and out of the herb garden – lavender.
Most woody herbs can become sturdy, flourishing plants without much in the way of maintenance at all.
Equipment For Pruning Herbs
For a detailed look at how to select the right equipment for the job, you can check out my article How To Select A Pruner: The Complete Guide. In the meantime, as a general guideline, you will need:
- Fingers
- Scissors
- A good pair of bypass pruners.
Light Pruning Techniques For Herbs
The most important thing to remember when pruning your delicate herbs is what you shouldn’t do, namely:
Don’t remove too much plant
More specifically, don’t cut off the larger leaves, especially those near the base of a plant. Why? Because those are the leaves that are most important to the health of your plant. The larger leaves soak up significantly more sunlight than the smaller, newer growth and your herbs can suffer greatly if these bigger “sun sinks” are removed.
In addition, do not cut back more than half of a healthy plant. If you do so you’re likely to see your herb die off. This is because it is especially difficult for a plant to rebound from such a significant reduction in its size.
Tipping, also known as pinching, is a technique used on young plants to encourage branching. However. Just to be confusing, those terms are also used for the practice of removing buds to discourage branching.
When your herb first breaks the surface of the soil, it will do so with a single stem. The growth of your plant will be led by this single stem. Assuming your herb branches out and becomes bushier this single stem will eventually allow buds to open up and become more lush. By pinching out the tip you will encourage your herbs to “bush” sooner than they would if the plant was left to its own devices.
How To Pinch Or Tip The Right Way
Before you begin to tip your plant, wait until it has grown at least three pairs of leaves. Until this stage, your plant is just too young to begin pruning. At the base of each leaf, just above where the leaf is emerging from the stem, you will see buds. This point of the plant is called the node. On some plants, you will see a horseshoe shape mark where a stem has detached. This marks the location of the node. The lengths of a stem which grow between the nodes are called internodes.
To correctly tip, or pinch, your herb use your fingernails or a tiny pair of scissors to pinch the stem, just above the node. It is vital to avoid damaging the new buds growing at the base of the existing leaves. If you pinch two closely and damage the buds they will fail to grow correctly.
As long as you have been careful, and have not damaged them, you should see the buds begin to open up to form new stems. You can repeat the entire process once these new stems have developed three pairs of leaves.
If you are pinching a flowering herb the flowers will not grow while you are actively pinching. Instead, you will have to wait until the plant has reached your desired state of bushiness and then stop pruning. Only then will the plant be able to flower.
Hard Pruning Techniques For Herbs
In the case of woody herbs, you should begin your pruning by removing any dead or diseased branches. This can be done at any time of the year and you can cut these back to ground level if you wish.
Then, when new growth is just beginning to emerge, usually during spring, you can use pruning shears to cut back up to a third of each stem. Do not cut back any more than this at a time or you risk damaging the plant to such a degree it cannot recover. If you need to drastically reshape or cut back your plant, you will have to do so over two or three years, trimming up to a third of each stem each year.
Be careful not to prune towards the end of the growing season as you do not want your herbs producing new, tender growth just as winter begins to set in.
When Should You Prune Your Herbs?
When you prune your herbs depends, to some degree, on why you are pruning. In all cases, you can prune annuals right up until the first frost hits. After this, it is still ok to harvest your herbs but you are likely to find that the quality takes a nosedive very quickly. You should stop pruning or harvesting biennials and perennials one month before the first frost is forecast.
- Pruning to promote growth and production: When you have a young plant or an older plant that you want to reinvigorate, you can prune during active growth. What is more important, in this case, that you prune carefully, so as not to damage the delicate buds at the nodes.
- Pruning to control a plants size and shape: If your objective is to prevent tall straggly plants or to restrict your plants to the space available, then you can tip/pinch out during the active growing season. In addition, for biennial or perennial plants, you can prune during their dormant period. The thing to remember is that you should not prune towards the end of the growing season as this can stimulate new growth at a time when the plant should be directing its energies into “shutting down” for the winter.
- Pruning to remove dead or diseased parts of your plants: If you spot yellowing, wilting, dead, or dying leaves of stems, you should remove them as soon as possible and not wait until the “correct” time to prune. The same timing applies to any part of the plant that displays signs of disease or damage from pests.
For some herbs, such as lavender and tarragon, you can harvest the flowers and cut back the entire plant in July. Depending on your location and the weather where you are, this should result in a second round of flowers before the end of the growing season.
Harvesting Your Herbs
The techniques for harvesting your herbs are much the same as those for pruning your herbs. It is still vital to ensure you harvest in such a way that the plant does not sustain any damage. By being gentle with your harvesting you can expect to be rewarded with a delicious, plentiful crop all season long.
The trick is to harvest in a way which encourages continuous growth of the part of the plant you want to use. For example, if you want to harvest the flowers or the seeds of your herb, the pruning regime you will follow is different to the one you will use on herbs where you will harvest the leaves and stems.
Harvesting The Stems Or Leaves Of Your Herbs
To keep your plants happy, healthy, and enthusiastically producing the most delicious leaves remember:
- Never harvest more than one-third of the plant at a time: If you do so, you risk killing the plant off entirely. Even if it doesn’t die the growth will be weak at best.
- Do not allow your plant to flower: If you are never going to use the flowers, don’t allow your plant to waste energy and resources to grow them. Not only that but when a herb begins to flower it changes the taste of the leaves and stems, often making them bitter and unpalatable. To avoid this pinch off any flower buds as soon as they appear.
- Don’t randomly pull leaves off of your plant: Remember when I wrote earlier, about pinching/ tipping your plant? This is always the way to harvest the leaves and stems you wish to use. When you pull off random leaves there is no way for the plant to regrow in that area because there will not be any buds primed to grow in their place. Not only that but your herbs need those larger, mature leaves in order to photosynthesize. Pull off random leaves often enough and you will be well on your way to killing off your herbs. There are two exceptions to this:
- If your plant is so big that it is not going to suffer from the loss of a couple of larger leaves here and there.
- When you have pinched out a stem lower down on the plant and a larger leaf is blocking out all of the daylight the buds need to grow.
- Do use the basic tipping/pinching technique for harvesting: In the same way that you want to prune just above the node, you will want to harvest in the same spot using your fingernails or a small pair of scissors for delicate herbs and pruning shears for the hardier members of your garden.
- For optimal flavor, harvest leaves in the morning, after the dew has dried but before the full heat of the day has arrived.
Harvesting The Flowers And Seeds Of Your Herbs
There are a number of different points to remember if you are harvesting the flowers or seeds of your herbs:
- Ensure your flowers or seed pods, are completely dry: If they are even slightly damp you run the risk of them beginning to rot. The exception to this is if you intend to use the fresh flower immediately.
- Choose where to cut them stem: If you cut just below the flowerhead it is likely, depending on the plant, that flowers will regrow. However, in this case, you will have nothing from which to hang your flowers for drying. On the other hand, if you cut the flower from the base of the stem you will have a nice long stalk from which to hang your flower, but little chance of regrowth. For the best of both worlds, you can cut the flower just above a node, in which case the plant will regrow with two stems instead of one.
- Have patience for seeds: To harvest seeds you will have to wait for the flowers to bloom and the seed pods to form. Then you have to wait a fair bit longer until the seed pods are beginning to dry on the plant. Only then can you finally cut off the seed pods. Seed pods are the final stage of your herbs lifecycle. If the seeds you are harvesting are from an annual you do not have to be that careful when pulling off the pods. Just be sure not to damage any pods left behind which are not yet ready for harvesting.
- For optimal flavor, harvest your flowers after they have begun to open, but before they have fully bloomed. In the case of seed pods, pick them as they begin to turn brown.
What To Do With Your “Prunings”
When you prune your herbs to promote growth, you may be left with lots of trimmings that could be put to good use. You can do one of three things to use your herbs:
- Fresh Use: The easiest, and most obvious thing to do with your herb trimmings is to use them there and then. However, you may not have the time, inclination, or appropriate food to use the herbs straight away. Some herbs with stems, such as basil, can be treated like cut flowers and placed in a container of water. This will keep them fresh for up to a week. Others, such as chives can be wrapped in a damp paper towel and stored in the refrigerator for up to a week.
- Dried Herbs: There are many ways to dry your herbs, either the flowers, leaves, or stems:
- The most traditional way, for low moisture herbs such as sage and parsley, is to bunch them together, tie with some string or twine and hang them upside down. You will want to hang them in a dry, dark, preferably warm, spot, where there is plenty of airflow around the herbs. It can take up to three or four weeks for the herbs to dry. When they are ready, strip the leaves from the stalks.
- Fore herbs with a higher moisture content, such as mint and lemon balm, you need to dry them more quickly to prevent rot. Strip the leaves from the stems and lay them out in a single layer on a drying rack. If you do not have a drying rack you can use any item that allows air to flow freely around both sides of the leaves.
In the case of both methods, store your dried herbs in an opaque, airtight container. Either a ceramic or glass jar is the best option as they will not affect the flavor of your herbs. Do not chop your herbs until immediately before you use them.
- Rerooting: Put your cut herbs trimmings into a jar with a little water, making sure to keep the majority of the herb trimming out of the water. Change the water every other day and after a few weeks, you should see new roots peeking out from your trimmings. Once these roots have emerged you can transplant your new plants into the garden.
Conclusion
Herbs are both an attractive and useful addition to your garden. The correct pruning techniques will ensure you have healthy plants throughout the year. The trick is to learn what type of plant your herb is, what kind of pruning is most appropriate for its health, and how to harvest your herbs without damaging the plant as a whole.
With this knowledge, you can not only keep your garden well stocked with lush, fragrant growth, but you’ll have a fridge and a pantry full of herbs to enjoy.