Growing food

Does Lemongrass Spread (and How to Stop It)?

If this is your first time growing lemongrass, whether in the garden or in a pot, you’ll want to know a little about its growth habit. The question that is commonly asked is whether lemongrass spreads.

Like most perennial grasses, lemongrass definitely spreads. Lemongrass is a fast grower when in the right conditions and will continue to spread throughout its growing season. In fact, when grown in the ground, it will continue to spread and spread unless you limit its growth.

When grown in a pot, your lemongrass can only spread as far as the confines of the pot will allow it to. However, it will definitely spread to fill the entire pot.

How Far Will Lemongrass Spread?

If you’ve planted your lemongrass in the ground, it will continue to spread until it either has nowhere else to go, or you limit its spread manually. In fact, lemongrass can easily spread two feet in all directions in just one growing season.

This means that if you don’t limit the spread and your lemongrass is growing as a perennial because you live in a warm climate, it could eventually take over your entire garden.

Many people grow lemongrass not only as a herb but also as a landscaping plant. Its spreading habit makes it great for growing along borders or other areas that will benefit from its pleasant display. However, you need to be aware of its constant spreading habit, so it doesn’t grow too far and crowd out your other plants.

Some people overcome this problem by planting lemongrass in pots. Remember that the plant can only spread as far as the pot will allow. This is a good way to contain your lemongrass clump to a confined area. But, you should remember that lemongrass is quite an aggressive grower, so if the pot is too small for the plant, the roots can eventually break through the pot.

How To Stop Your Lemongrass From Spreading Too Far

If you want to keep your lemongrass in a confined area, it’s not that difficult when you understand how it grows and are happy to do some regular maintenance on your plant.

As lemongrass grows, it continues to produce new shoots all around the edges. This is how the plant spreads so well. These new shoots then mature and start to put on some height, and all the while this happens, new shoots are continually forming around the perimeter of the plant.

When you understand this, there are various things that you can do to limit the spread of your lemongrass. For example, because lemongrass doesn’t have very long roots, you can put in a barrier that goes a couple of inches below the ground. This barrier should inhibit your lemongrass from continuing to spread beyond it.

It’s also possible to keep your lemongrass in large containers and half bury these in the ground. The walls of the containers will slow down the spread of the lemongrass.

Another thing that you can do to control the spread is to harvest your lemongrass often. When you harvest, cut the younger stalks from around the perimeter of the plant as these are part of the spreading habit of the plant.

Keeping your lemongrass well-trimmed will also help to limit its spread. You can do this with a sharp pair of shears. Just trim back all the leaves on a regular basis, especially during the growing season.

Dividing Your Lemongrass Clumps: The Best Way To Contain The Spread

One of the absolute best ways to limit the spread of your lemongrass is to divide the clumps. In warmer regions where lemongrass stays green all year round, this is best done in early spring before the plant comes out of dormancy.

On the other, if you’re growing lemongrass in a cooler zone where it won’t survive winter outdoors, you dig up your plants and divide them up in the fall. This then allows you to put the smaller clumps into pots that can live indoors over winter.

Here’s how to divide your lemongrass for plants that are grown outdoors all year round:

  • With this method, there’s no need to dig up the entire clump. All you’re doing is reducing the size of the clump to limit its spread and encourage new growth.
  • In early spring, take a very sharp spade and cut into the plant around the edges.
  • Once you’ve severed these sections from the main plant, just dig them out gently, making sure that the roots are attached to parts you’re digging out. You can do this right around the edges of the plant until you have the original clump at a more manageable size.
  • The parts of the clump that you’ve severed and dug out can now be planted in another spot in the garden or you can put them into pots and give some away to your neighbors, family and friends. Make sure that you keep a couple of these pots to place around your outdoor entertaining area to help keep mosquitoes away.
  • Because lemongrass is such a rapid grower you might want to do this every year or at least every couple of years to ensure your clumps don’t get too large.

Here’s how to divide lemongrass that is grown in a colder zone:

  • In the fall, as the weather starts to cool down, you’ll need to dig up your clumps of lemongrass as they won’t survive the winter outdoors.
  • It’s a good idea to reduce the height of your plant before you do this as it will be easier to manage. Just use a pair of sharp shears to cut through the leaves, reducing their length by about half.
  • Then, you want to dig up the entire clump and divide it up into smaller sections. You can use a sharp knife or secateurs to separate your plant into smaller sections.
  • Plant each section into its own pot and take these pots indoors to overwinter. Because lemongrass goes dormant in winter, it doesn’t have to be kept in a bright spot. You can even place your pots in the garage or the basement over the winter. They’ll only need a very occasional watering to keep the plants alive.

What To Do With Lemongrass Grown In Pots

Lemongrass that is only grown in pots also needs some regular dividing to ensure that it remains healthy and that the plant does not try to break through the sides of the pot.

This is also best done in early springs before the plant comes out of dormancy.

MokkieCC BY-SA 3.0, via Wikimedia Commons

Here’s how to divide lemongrass grown in a pot:

  • Remove any dead foliage and trim back the leaves to make it easier to handle the plant. Always remember to wear gloves when handling lemongrass because the leaves have sharp edges that can easily cut you.
  • Take the plant out of the pot and shake off as much of the soil as possible.
  • With a sharp knife, separate the clump into smaller sections. Make sure that each section has plenty of healthy roots attached.
  • Plant each section into its own pot that has been filled with premium quality potting mix.

You now have extra plants that you can either keep or give away to family and friends. Pots of lemongrass are also great for selling at market stalls or as fundraisers for your local school or sporting club.

Now that you understand how lemongrass grows and spreads, you can not only decide on the best place to plant it in your garden but also how to control the spread. If you give your plant some regular maintenance by trimming and removing the outer growth on a regular basis, you won’t have it invading other areas of your garden.

If you would like to know more about this topic, please check the complete guide I wrote about growing lemongrass.

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