Knowing how to prune lemongrass for winter is a key skill for keeping your plants alive in colder climates. This essential cold weather preparation makes the difference between a plant that rebounds in spring and one that doesn’t survive the frost. If you love the citrusy aroma of lemongrass in your teas and dishes, a little autumn care is well worth the effort.
Lemongrass is a tropical perennial, which means it thrives in warmth. When temperatures drop, its growth slows and the outer leaves can become damaged. Proper pruning helps the plant conserve energy, reduces the risk of disease, and makes protecting it much easier. Let’s get your lemongrass ready for the cold months ahead.
How to Prune Lemongrass for Winter
This main pruning session is done in late fall, just before your first expected frost. The goal is to tidy up the plant and remove any growth that could rot or harbor pests over winter. You’ll need a pair of sharp, clean pruning shears or hedge trimmers for larger clumps, and a pair of gloves to protect your hands from the sharp leaf edges.
Step-by-Step Pruning Instructions
- First, assess your lemongrass clump. Identify any dead, brown, or yellowing leaves on the outside of the plant. These are the first to go.
- Using your shears, cut all the leaves back to a height of about 6 to 12 inches above the ground. Aim for a uniform, rounded shape. It might look drastic, but this removes the bulk of the tender foliage that is most suseptible to cold damage.
- As you prune, clear away any debris or dead material from the base of the plant. This improves air circulation and prevents mold from developing around the crown.
- If you are in a very mild climate (USDA zones 9-10), this light pruning may be all you need before winter. For colder zones, this pruning is the essential first step before applying insulation.
What to Do With the Cuttings
Don’t throw those fragrant cuttings away! The tender, pale lower parts of the stalks are still usable in the kitchen. Simply trim off the tough, green tops and the woody root end. You can chop and freeze the good parts for cooking. The tougher green leaves can be dried and used to make a soothing herbal tea.
A Note on Fall Harvesting
Many gardeners choose to do a final harvest at the same time as pruning. You can dig up a portion of the clump, separate a few stalks with roots attached, and pot them up to grow indoors on a sunny windowsill. This gives you fresh lemongrass all winter long and acts as a backup in case your outdoor plant doesn’t make it.
Post-Pruning Winter Protection Strategies
Pruning alone isn’t enough in areas with freezing winters. After you’ve cut the plant back, you need to insulate the crown and roots. The method you choose depends on your local climate.
- For Mild Frosts (Brief dips below freezing): After pruning, mound 4-6 inches of dry mulch, like straw, shredded leaves, or pine needles, over the entire pruned clump. This acts like a warm blanket.
- For Hard Freezes: In addition to heavy mulching, consider placing a burlap sack or frost cloth over the mulched plant. Secure it with twine to keep the mulch in place and the wind out.
- For Container Plants: The easiest method is to move pots into a garage, shed, or basement where temperatures stay above freezing but stay cool. Water very sparingly, just enough to prevent the soil from completely drying out, about once a month.
Common Pruning Mistakes to Avoid
A few errors can compromise your lemongrass’s health. First, avoid pruning too early in the fall. Cutting back while the plant is still actively growing can stimulate new, tender growth that will be killed by the first frost. Wait until growth has slowed and frost is imminent.
Second, never cut the plant down to the ground. Leaving that 6-12 inch stub is crucial. It protects the plant’s central growing point (the crown). If you cut it flush with the soil, you risk exposing the crown to rot and cold, which can be fatal.
Finally, using dull or dirty tools can crush stems and introduce disease. Always make clean cuts. A quick wipe of the blades with rubbing alcohol before you start is a good habit.
Spring Awakening: What to Expect
As spring arrives and the danger of frost has passed, carefully remove the winter mulch from your lemongrass. Be gentle to avoid damaging any new shoots that might be starting. You’ll likely see new green growth emerging from the center of the pruned stubs.
Once you see consistent new growth, you can feed the plant with a balanced fertilizer to support its recovery. Resume regular watering as the weather warms. If the winter was harsh, some outer stubs may be dead; you can gently tug or cut these away to make room for the fresh growth.
When to Divide an Overgrown Clump
Early spring, after you’ve removed winter protection, is the perfect time to divide a mature lemongrass plant that has become too large. Dig up the entire clump and use a sharp shovel or knife to cut it into smaller sections, each with its own roots and shoots. Replant one section and share or pot the others. This rejuvenates the plant and gives you new plants for free.
FAQ: Lemongrass Winter Care
Q: Can I just bring my lemongrass plant inside for the winter?
A: Absolutely. Potted lemongrass does very well brought indoors. Place it in your sunniest window and reduce watering. It may not grow much, but it will stay alive untill you can move it back outside.
Q: My winters are very cold. Should I just treat lemongrass as an annual?
A> While you can grow it as an annual, overwintering is worth a try. After pruning and heavy mulching, some gardeners in zone 7 even succeed by placing an overturned plastic pot (with ventilation holes) over the mulched clump for extra insulation. It’s often more cold-hardy than people think.
Q: How do I prepare lemongrass for winter in a pot?
A: For potted plants, the simplest method is to prune it back as described, then move the pot to a cool, dark place like a basement. Let it go dormant and water minimally. It will look dead, but often resprouts in spring.
Q: Is fall the only time to prune lemongrass?
A: Major pruning is best in fall. During the growing season, you can harvest stalks as needed by cutting them at the base, which keeps the plant tidy. Avoid a heavy prune in summer, as it can stress the plant during heat.
Q: My lemongrass leaves are turning brown in fall. Is this normal?
A: Yes, this is a normal sign of the plant entering dormancy. The outer leaves often brown as temperatures cool. This is your signal that it’s almost time for your essential winter pruning and prep.
Following these steps for how to prune lemongrass for winter will give your plant the best chance to survive the cold. With proper cutting and protection, you can enjoy this flavorful herb returing year after year, growing larger and more productive with each season. Remember, the key is timing, a clean cut, and generous insulation.