Common Herbs With Weedy Ways




Don’t let weedy herbs run amok in your garden! Illustration: confessionsofacomposter

Who doesn’t enjoy fresh herbs, those aromatic plants that add such punch to our meals? Or treat our sniffles or upset stomaches? And they’re never fresher than when we grow them ourselves. That’s why herbs are presently so popular: everyone wants to try them. And most people find them easy to grow… at first. But many herbs have a major downside: they’re moderately to highly invasive and can quickly switch from being useful plants to becoming out-and-out garden thugs.

Two Categories of Weedy Herbs

20170425C WC.jpg

Borage is an easy-to-grow annual herb… perhaps too easy to grow, as it can self-sow so abundantly that it becomes a weed. Photo: Wikimedia Commons

There are two categories of potentially weedy herbs: those that produce creeping rhizomes or stolons (or sprout from broken pieces of root) that head off in all directions, soon producing offsets that surround and overwhelm neighboring plants, and those whose invasive habits are due to self-sowing, giving hordes of babies from the seeds they drop, hordes that can quickly threaten your entire herb garden.

Here is a list of the “main culprits” along with their preferred mode of invasion:

  1. Borage (Borago officinalis): seeds
  2. Caraway (Carum carvi): seeds
  3. Catnip (Nepeta cataria): seeds
  4. Chamomile (Matricaria recutita): seeds
  5. Chervil (Cerefolium anthriscus): seeds
  6. Chives (Allium schoenoprasum): seeds

    20170425H.UserSB_Johnny, WCJPG.JPG

    Perilla or shish is a popular Chinese herb, but self-sows like the dickens. Photo: User:SB_Johnny, Wikimedia Commons

  7. Comfrey (Symphytum officinale): seeds and root sections
  8. Coriander or cilantro (Coriandrum sativum): seeds
  9. Costmary (Tanacetum balsamita): seeds
  10. Dill (Anethum graveolens): seeds
  11. Fennel (Foeniculum vulgare): seeds
  12. Feverfew (Tanacetum parthenium): seeds
  13. Garlic chives (Allium tuberosum): seeds
  14. Horseradish (Armoracia rusticana): root sections
  15. Lemon balm (Melissa officinalis): seeds
  16. Mint (Mentha spp.): stolons and creeping stems
  17. Monarde (Monarda didyma): rhizomes
  18. Mustard (Brassica nigra and B. juncea): seeds
  19. Origan (Origanum vulgare): seeds

    20170425F, Cillas, WC.jpg

    Russian tarragon (Artemisia dracunculoides) can become a garden weed. Photo: Cillas, Wikimedia Commons

  20. Russian tarragon (Artemisia dracunculus): rhizomes and seeds
  21. Shisho or perilla (Perilla frutescens): seeds
  22. Sweet cicely (Myrrhis odorata): seeds
  23. Sweet woodruff (Galium odoratum): rhizomes
  24. Tansy (Tanacetum vulgare): rhizomes and seeds
  25. Thyme (Thymus vulgaris): seeds
  26. Valerian (Valeriana officinalis): seeds

How to Control Weedy Herbs

Weedy or not, several of the herbs presented above are essential to any herb garden. Can you even imagine cooking without thyme, oregano or chives? But fortunately there are ways to grow weedy herbs while limiting their ability to invade. Here are a few:

A. Self-Sowing Herbs

20170425E, WC.jpg

Harvesting early and often prevents the plant from going to seed. Photo:, Wikimedia Commons.

  • Either remove all their flowers or harvest them before any seeds ripen;
  • Apply 3 to 4 inches (7 to 10 cm) of your choice of organic mulch (shredded leaves, wood chips, forestry mulch, etc.) throughout the herb garden, completely covering the soil. Seeds will not germinate in mulch-covered soil;
  • Hand pull when plants are still small;
  • Grow them beyond their hardiness zone. For example, fennel is hardy from zone 6 to 9 and can be weedy there if you let it go to seed. However, it won’t be invasive in zones 1 to 5.

B. Herbs With Wandering Rhizomes and Stolons

  • Cultivate them in pots on a deck, patio or balcony: that will nip any spread in the bud;


    Peppermint (Mentha piperita) grow inside a barrier made of sunken pots.

  • Plant them inside a barrier sunk into the ground. This could simply be a plastic pot or pail with its bottom removed. The barrier should stick up at least 2 inches (5 cm) above the ground as the rhizomes of some plants, such as mint, right will creep right over a barrier that is level with the ground.


Don’t hesitate to grow herbs: most are great and very productive plants and you’ll be thrilled with the results. But do take note of the invasive ones. After all, forewarned is forearmed!20170425G

Cilantro: Herb of the Year 2017

20170330B Forest & Kim Starr, WC.jpg

Young cilantro leaves look much like parsley. Photo: Forest & Kim Starr, Wikimedia Commons

Every year, the International Herb Association names a medicinal, culinary, or decorative plant Herb of the Year and their 2017 choice is coriander.


The exact origins of coriander (Coriandrum sativum) are lost in the mists of time, because the plant was already widely disseminated throughout much of the Old World well before the modern age. However, ethnobotanists believe it originally grew wild in the Mediterranean basin and the Middle East. It was certainly known to the ancient Egyptians and Greeks as well as to the Romans.

The name coriander is also of uncertain origin, but one of the more intriguing suggestions is that it derives it from the Ancient Greek kóris for stink bug, said to have a similar smell.


Coriander is quite typical of plants in its family, the Apiaceae, with a rosette of deeply cut leaves at the base giving rise to a leafy upright stem topped by domes of small flowers.


Botanical illustration of coriander. Compare the deeply cut leaves at the top of the plant to the younger, broader leaves above.

It’s an annual that reaches about 1 to 2 feet (30–60 cm) in height, sometimes more. The leaves that form the rosette are the ones usually harvested. They are medium green and fairly broad, diversely lobed with a toothed margin. In the rosette phase, it looks quite a bit like its close relative, parsley (Petroselinum crispum), and indeed is sometimes called Chinese parsley. The leaves of the top of the plant are more finely cut, giving maturing plants a very feathery appearance.

20170330D H.Zell, WC.jpg

Coriander flowers: note the extra-long petals on the outside of the umbel. Photo: H. Zell, Wikimedia Commons

The flowers are borne at the top of the plant in small umbels. The tiny flowers are white or very pale pink. Those on the outside of the umbel bear asymmetrical petals, distinctly longer than the others. They do an excellent job of attracting pollinating and beneficial insects to the garden, especially hoverflies and ladybugs.

Even before the flowering has finished, the foliage will already be yellowing. The seed capsules mature rapidly and release their seeds, then the plant dies.

One Plant, Two Names


Coriander seeds

Northern Europeans mainly use dried coriander seeds as a condiment, a tradition that was also adopted in northern North America and Australia, while in Asia and South and Central America, populations mainly harvest the foliage.

20170330E, Thamizhpparithi Maari, WVC.JPG

Coriander leaves are sold under the name cilantro.

Currently, under the influence of Mexican cuisine, the use of leaf coriander is gaining ground in North America under its Spanish name cilantro. In supermarkets, you usually see the Spanish name. Most people probably don’t realize coriander and cilantro are the same plant, just harvested at two different periods.

Besides being used as a culinary herb, both leaves and seeds of coriander are used medicinally, especially to treat gastric problems. Seeds also give an essential oil used in aromatherapy, perfumery and the food industry.

Of Questionable Taste

Curiously, the leaves and seeds don’t have the same flavor.

The leaves, used extensively in Asian and Mexican cuisines, have a refreshing taste a bit like parsley with a lemon bite to it, but it is certainly not everyone’s cup of tea. Many people say they taste and smell the soap… or worse! This disdain seems partially genetic and tends to run in families.

To my own nose, coriander leaves do indeed smell like a somewhat squashed stink bug… but then I find stink bugs, which obviously repel some people or they wouldn’t have that name, actually smell quite pleasant.

There is less controversy about the somewhat citrusy flavor of the seeds, which generally seem acceptable to all and are widely used in marinades and curries.

Growing Coriander

20170330G Lazargagnidze, WC.jpg

Coriander quickly goes to seed. If you want to use the leaves, you have to harvest them young. Photo: Lazargagnidze, Wikimedia Commons

Novice gardeners often complain that they failed with coriander. But actually, they probably didn’t fail. They just didn’t understand that they have to harvest it promptly. Only a week or so goes by between the plant being ready to harvest and it turning brown and dying. You have to be fast when it comes to coriander!

That’s why I don’t recommend buying pots of already-started coriander, even though most garden centers (and supermarkets) sell them that way. Those plants are just about to bolt (go to seed) when you buy them and will probably do so shortly after you get them home. And as soon as they start to bolt, the foliage becomes bitter and is no longer edible. Why go through that?

It is far easier to sow this herb yourself from seed, sowing it directly in the ground where you want it to grow. Coriander seeds are widely available, probably in local garden centers; if not in just about any catalog that offers herb seeds.

Sow the seeds about ¼ inch (5 mm) deep and about 1 to 2 inches (3 to 5 cm) apart, starting in early spring, as soon as the soil can be worked. Repeat every 2–3 weeks: that way, you’ll have leaves to harvest throughout the summer and into fall.

You can also sow coriander outdoors in late fall to ensure the first harvest the following spring. In countries with mild winters, in fact, coriander is generally grown as a winter herb, as the cool days and even cooler nights (it will take some frost) help keep it from bolting.

The Laidback Gardener Method

The most laidback way to grow coriander is to let it self-sow.

The first time you grow it, simply let a plant or two go to seed. The seeds will then fall to the ground and germinate, providing a few seedlings at a time for most of the summer. From then on, let at least one plant go to seed each year and you’ll end up with a self-maintaining coriander supply, despite the very short life of each individual plant. Of course, you’ll discover that coriander doesn’t always sprout where you want it to, making it officially a weed… but at least it’s an edible weed!

Coriander prefers full sun or light shade and well drained, slightly acid soil (a pH of about 6.0 to 6.8) of just about any quality.

Coriander is rarely sown in rows. Instead, traditionally a few seeds are sown here and there among the other vegetables and herbs. It can also be sown in pots outdoors, normally near the edge of a pot containing other herbs or vegetables.

Thin the seedlings to 15 to 30 cm apart… and use the seedlings you remove by thinning in the kitchen as your first harvest.

Keep the soil slightly moist during the (very short) growing season. Covering the soil with mulch will keep the soil cooler and help delay bolting.

There is no need to go out of your way to fertilize coriander. Instead, just maintain good soil quality for the other herbs and vegetables and coriander will benefit from it.

Coriander grows best in spring and fall, but goes to seed rapidly in the heat of the summer. Sometimes you only have time to harvest a few leaves per plant from summer-grown coriander. Or simply harvest the seedlings as sprouts.

Growing Indoors


Coriander sown indoors for use as sprouts.

Coriander does not make a good indoor plant. Not only is it difficult find the intense sun and the cool temperature it prefers, but it’s sensitive to plant pests when grown indoors. Instead of trying to force a recalcitrant plant to grow to full maturity, though, try sowing and harvesting young plants before they start to degrade.

Sow the seeds in a pot or tray in moist soil, supplying the most intense lighting you can. The leaves will be small, but there should be plenty to harvest in just 3 to 4 weeks. Repeat sow every 2–3 weeks to ensure a continuous supply.



Just by thinning these seedlings, you’d get a good harvest of leaves.

You can harvest coriander leaves at any time until the plant starts to bolt, from the time it is a seedling until it has formed its full rosette. Just cut off each leaf at the base. You can harvest up to one third of any given plant’s leaves at one time and it will replace them.

Coriander leaves don’t dry well. They can be frozen or stored in oil, but then lose a lot of their taste. It’s best to use them fresh.

As for the seeds, harvest them from the plants which you’ve allowed to go to seed. As soon as the capsules begin to turn brown, cut the stalks and place them inside a paper bag (some sources suggest they have to be upside down in the bag, but you can place them right side up or sideways: it makes no difference). Don’t wait too long to harvest them or the capsules will split open and you’ll lose the seeds!

The seeds are already dry when your harvest them and will readily keep for at least 4 or 5 years.


There are several varieties of coriander, but if you want to harvest leaves for the longest possible season, consider varieties that are known to be slow to bolt, such as ‘Calypso’, ‘Long-Standing’, ‘Marino’ or ‘Slow Bolt’. If growing for seed, though, these would be the worst choices!


20170330J Jean-Paul Bigand, WC.jpg

Vietnamese coriander (Persicaria odorata) is in no way related to true coriander, but has a similar taste.

Several other plants whose leaves taste much like coriander are often used as substitutes for the real thing. This is particularly the case with culantro (Eryngium foetidum), Bolivian coriander (Porophyllum ruderale) and Vietnamese coriander (Persicaria odorata, syn. Polygonum odoratum).

Good growing!20170330B Forest & Kim Starr, WC