Filling your garden with vibrant lavender plants adds a lot of visual appeal to the space. However, you might find that your lavender plants are spreading too much. Lavender can extend up to 40 inches (102cm) and grow to around two feet (0.6 m) tall, so how can you prevent your lavender from spreading excessively?
You can stop your lavender from spreading by growing it in pots. In the garden, you can trim and prune your lavender plants to maintain their shape and keep them compact.
In this article, I’ll explore 14 practical tips you can follow to stop your lavender from spreading too much. Let’s get started!
1. Trim Lavender in Late Summer
If you don’t supervise and maintain your lavender plant regularly, it can quickly overgrow, so you need to trim and prune it to keep it as compact as possible. Ideally, you should trim lavender late in the summer, once it has completed flowering.
Here’s how to trim your lavender plants.
- Remove spent flower stalks on the lavender.
- Remove approximately one inch (2.54cm) of foliage growth.
Avoid pruning lavender in the fall because this could cause the plant to struggle to thrive in cold weather.
You can use pruning shears with a sharp blade to prune your lavender.
2. Keep Lavender in Containers
Since lavender is a self-seeding plant, you might want to prevent it from spreading in the garden by keeping it in containers.
One of the best types of containers for lavenders is one that’s made out of ceramic. This is a thick material that preserves more moisture than a pot that’s made out of plastic or metal. This is especially important because lavender plants require water every two weeks, and you should give them approximately four-and-a-half cups (1 liter) of water each time.
If you keep your lavender in a planter box, it shouldn’t be too deep to allow for proper drainage. Read my blog post to choose the best size planter box for your flowers: How Deep Does a Planter Box Need to Be for Flowers?
3. Rotate the Lavender Pot
You want to give your indoor lavender plant at least three or four hours of direct sunlight daily. Ensure that you rotate the container or pot every few days so that the plant will grow evenly. This also helps to prevent it from spreading or stretching in certain directions as it struggles to reach the light.
Lack of sunlight can also cause lavender to grow spindly, so you want to ensure that you carefully oversee its sunlight exposure.
4. Prune Young Lavender Plants Annually
You should prune your lavender plants when they’re small. This will ensure that they can produce roots and stems, and become mounded, which means they gain a rounded appearance.
Here are some essential tips to bear in mind when pruning your lavender plants.
- Start by pinching off new growth tips on the plant. This encourages the lavender to produce dense branches so that they will have a round shape.
- Cut the plant back by about one-third. Aim to keep the outer stems a bit shorter than the central ones, as this will give the plant a beautiful rounded shape and keep it compact, as Garden Gate Magazine reports.
- Resist the temptation to only prune when the plant is mature. Avoid not pruning lavender until it becomes mature, as this will encourage woody growth that you’ll struggle to shape and maintain as easily, causing your lavender to spread and look unsightly.
5. Split Your Lavender Plants
Splitting your lavender is important when it comes to maintaining it and preventing it from getting too large. You can split your lavender plant by following a process called layering.
Lavender is a type of woody perennial that can propagate itself by forming new plants when a branch makes contact with the ground and produces roots. That’s why layering can help to keep it under control because it essentially keeps the lavender closer to the ground so it can be compact.
Here’s how to layer your lavender:
- Measure eight inches (20.32 cm) from the growing tip.
- Cut away leaves from this section.
- Leave about six inches (15.24 cm) of leaves that are on the stem near the plant base.
- Dig a hole that’s approximately four inches (10.16 cm).
- Spray a mist of water on the stem end and put it into the hole.
- Sprinkle a bit of rooting hormone on the stem end.
- To secure the branch in the ground, use a bit of wire.
- Cover the branch with soil.
- Water it regularly.
- The next year, it cut the branch away from the parent plant. You can do this with pruning scissors. You should now see some healthy roots.
- Replant the lavender in a sunny spot in your garden.
6. Choose a Dwarf Variety of Lavender
If you want to prevent your lavender plant from spreading too much, you should consider planting a dwarf variety, such as ‘Thumbelina Leigh’ (Lavandula angustifolia). This is one of the smallest types of lavender as it grows to a maximum height of 12 inches (30cm). It also performs well in containers or pots.
Other lavender varieties that stay small and compact include the following:
- ‘Little Lady’ (Lavandula angustifolia). This dwarf lavender variety works well in low borders in the garden, or you can place it in pots for indoor use. It reaches a height of 20 inches (50cm). It displays gorgeous, fragrant flowers.
- ‘Fairy Wings Radiance.’ This is a modern lavender variety that’s resistant to drought conditions. It reaches a height of 24 inches (70cm) in height and width. It displays pink petals on top of its flower spikes.
- ‘Nana Alba’ ( Lavandula angustifolia). This plant has green and silver leaves as well as white flower spikes to create beautiful contrast. It reaches a height of 12 inches (30cm).
7. Deadhead Lavender Flowers Regularly
Lavender is self-seeding, which can occur if you leave flower stalks on the plant. This process produces small lavender plants within close proximity to the original plant. If this is something that you don’t want to see in your garden, you should dead-head your lavender plant regularly.
This basically means removing its spent flowers. Lavender seeds are produced inside the plant’s blooms. You can separate these seeds from the flower head by simply shaking them after they’ve been dried.
Cutting the lavender flower heads in late summer is also a good way to prevent the plant from spreading.
Although it’s said that lavender plants don’t usually need to be dead-headed, this can help them remain small and compact. This is especially beneficial if you’re using lavender as a border plant next to walkways. The good news is that dead-heading won’t harm the plant in any way.
Here’s how to dead-head lavender:
1. Find the flower that’s on the top of the plant’s stem.
2. When you run your finger down the stem, stop when you find a set of leaves.
3. Cut the stem above the leaves.
4. Repeat with all the stems on the plant.
Deadheading plant offers a wide a array of benefits, such as:
- It prevents lavender from wasting its energy and resources on flowers that are nearing the end of their life.
- It encourages the plant to direct energy to produce new flowers.
- It makes flowers grow healthier and larger.
- It prevents plants from becoming leggy or losing their tidy, compact shape.
8. Choose the Correct Lavender Variety
Some types of lavender will grow back every year, but others won’t be able to survive the harsh winter. So, if you don’t want your lavender to grow back, choose a variety such as French and Spanish lavender. Both of these varieties are not cold hardy, so they might not return after a freezing winter.
On the other hand, English lavender is a hardy variety.
However, you need to consider other pros and cons of these hardy and non-hardy plants so that you get the one that you really want. English lavender is appealing because of its pleasing scent, but French lavender has a stronger aroma.
When it comes to their appearance, French lavender features long petals at the tip of its flower and tends to be darker in color than its English counterpart, which has cone-shaped flowers on a thin stem.
9. Prevent Lavender From Being Woody
Lavender plants can become woody, which means that their stems don’t produce fresh green growth. When this happens, you’ll be left with a woody plant that doesn’t produce new shoots that can flower.
To prevent this, it’s essential to prune your lavender to slow down the formation of woody stems. Ideally, you should prune your lavender annually. The best time to prune lavender to prevent woody stems is after the plant has finished its blooming cycle. Ensure you remove shoots about one inch (2.54cm) below the previous year’s growth.
By cutting the plant down to where you can see new growth coming out of the plant, you’ll encourage it to grow vigorously while also maintaining its shape so it won’t spread and become untidy.
10. Plant Lavender in Areas With Less Light
It’s tricky to reduce the amount of light that your lavender plants get because you don’t want them to be in very shady conditions that will prevent them from growing.
However, giving your lavender too much sun every day can cause it to spread faster. This is why it can be good to give your lavender indirect light every day – this strikes the right balance between too much and too little sunlight,
Indirect sunlight exposure occurs when the light doesn’t reach your plant directly because something is in the way. So, for example, if you place your indoor lavender plant behind sheer curtains or you place your outdoor lavender plant underneath a taller plant that diffuses the light the plant receives, it is receiving indirect light.
11. Decrease How Much You Water Your Lavender Plant
Generally, you should water your lavender once or twice a week until the plants have become established. When your plants are mature, you should water them every two or three weeks until you can see flower buds starting to form on them. If your lavender plant has leaves that are becoming yellow, this is a telltale sign that you’re overwatering it.
The great thing about lavender plants is that they don’t need a lot of water, so avoid watering them too much as it can cause them to grow very quickly so they spread while increasing their risk of fungus, root rot, and other diseases.
It’s important to note that lavender has shallow roots, which makes it susceptible to root rot if it’s watered too much, as The Spruce reports. This disease can be fatal for your plants.
12. Stop Fertilizing Lavender Too Much
Although fertilizer is healthy for lavender, which craves nutrient-rich soil to grow and thrive, you shouldn’t give it too much as this can cause it to become overgrown. Too much fertilizer causes the lavender to grow too many leaves, which can make it appear unruly. In addition to this, you might see that your lavender plants don’t bloom, which usually occurs if your fertilizer contains too much nitrogen.
When fertilizing lavender, follow these tips to keep your plant healthy without it becoming unruly.
- Fertilize young lavender plants in spring. This should be done just as the growing season is starting.
- You should use a diluted, general-purpose fertilizer as this is ideal for your lavender plants. A 15-15-15 fertilizer works well.
- Apply one inch (2.54cm) of fertilizer. This should be applied around the lavender plant, and it’s enough to keep the lavender healthy for the whole year.
- Don’t fertilize mature lavender plants unless they’re struggling to grow.
- If you notice signs on the plant that indicate the fertilizer is negatively affecting it, such as that it’s not growing as much foliage or flowers, stop using it.
13. Reduce the Height of Your Lavender Plants
Although pruning and trimming your lavender plants is important, we don’t usually think about reducing the lavender’s height, but this is a good tip that will help keep your lavender small and compact.
Don’t neglect cutting it back from the top every two or three years. This entails reducing the height of your lavender plants by approximately six inches (15.24cm).
This will keep your lavender compact, and it also prevents the plant from becoming thin or scraggly. Instead, it encourages it to grow denser. This is ideal when you want your lavender plant to become bushier, and it makes it easier to shape so that it’s an ornamental plant in the garden.
14. Plant Lavender in Well-Draining, Sandy Soil
If a plant is called leggy, this means that it’s growing long stems without many leaves on top. Sometimes plants can become leggy because they aren’t receiving enough sunlight, so they start stretching and reaching for the light.
However, your lavender plants can also become leggy if they haven’t been planted in the correct soil. If the soil is too compacted or fertile, your lavender will struggle to grow.
You can test how well your soil drains water by digging a 12-inch (30.48cm) deep hole and filling it with water. Wait a few hours to see how quickly the water drains. If you can see that it moves too slowly, you can enhance its drainage by adding vermiculite or perlite to the soil.
I’ve written an extensive guide about creating the ideal growing conditions for lavender plants, don’t miss it: Should You Add Sand to Soil for Lavender Plants?
If you’re growing lavender in pots, make sure that the pots contain drainage holes at the bottom. These holes will prevent the plants from sitting in too much water.
Final Thoughts
Although lavender plants make for an excellent addition to any garden, especially when they release their beautiful scent, it’s disappointing when they start to spread and become so large that they encroach on other plants. You can prevent lavender plants from spreading or becoming unsightly by following tips such as:
- Not overwatering your plants.
- Dead-heading lavender flowers.
- Pruning lavender every year.
- Avoiding the overuse of fertilizer.
