How to Prune Lavender to Prevent Woody Growth | Timing for Post-Bloom and Hard Pruning, and Tips by Variety

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Many people who grow lavender have likely experienced the moment when they realize the base of the plant has become hard and woody, and no new shoots are appearing. This is a phenomenon known as "woodiness" or "lignification."

While woodiness is a natural characteristic of lavender, if it progresses too far, the plant's appearance will deteriorate and its flowering will decline.

In this article, we will explain everything from the mechanism of woodiness to specific methods for post-bloom pruning and hard pruning, as well as management tips to keep your lavender beautiful for a long time.

🌿 Why does lavender become woody?

Plants are broadly divided into "woody plants" and "herbaceous plants." Woody plants are what we call trees that form trunks, while herbaceous plants are what we call grasses or flowers with relatively short lifespans for their above-ground parts.

Lavender does not fit perfectly into either category and is classified as a "semi-woody plant." It has a nature of gradually becoming woody from the base as it grows, which is a natural physiological phenomenon for lavender.

The problem arises when woodiness progresses too far. When the base becomes hard and thick, it becomes difficult for new shoots to emerge from there, causing branches to concentrate only at the top and throwing off the balance of the entire plant. Additionally, if the inside of the plant becomes dense and airflow is restricted, it becomes prone to "stuffiness"—something lavender particularly dislikes—which, in the worst case, can lead to rapid wilting.

It is helpful to think of woodiness as having two stages: "a state where new shoots are still emerging from the base" and "a state where no new shoots are appearing." In the former case, recovery can be expected with proper pruning, but in the latter, it becomes quite difficult to manage. Therefore, it is most important to address it with regular pruning before woodiness progresses.

☑️ There are two types of lavender pruning

Lavender pruning is broadly divided into two types: "post-bloom pruning" and "hard pruning." Since their purposes and timing differ, use them appropriately according to the state of the plant.

Post-bloom pruning | Basic annual care

The flowering period of lavender varies by variety, but most common English (angustifolia) and French (stoechas) types bloom around May to June. Note that there are also ever-blooming lavender varieties, in which case it is standard to perform post-bloom pruning every time they flower.

The procedure for post-bloom pruning is as follows.

First, cut the flower stems from near the base and harvest the flower spikes. At this point, you can use the flower spikes as herbs or make dried flowers.

Next, trim the branches and leaves to a dome shape (a round, bushy form), using about half the height of the entire plant as a guide. The key here is to prune carefully so as not to crush the small new shoots at the bottom or inside of the plant. Leaving new shoots near the base leads to a beautiful plant shape the following year.

Furthermore, thinning out branches that are crowded inside the plant can prevent stuffiness. Since lavender dislikes high temperatures and humidity, ensuring good airflow before the rainy season is key to successfully getting the plant through the summer.

After pruning, the plant will be slightly smaller, but the next growth will begin immediately from the new shoots. There is no need to worry about cutting too much. In fact, if you leave it unpruned, woodiness will progress rapidly, so it is important to make annual post-bloom pruning a habit.

Hard pruning | Resetting when woodiness has progressed

If the plant has grown large and woodiness has become noticeable, perform a bold hard pruning. The target timing is during the dormant period from October to March of the following year, but in regions with severe winter cold, cutting back too hard when new shoots are not yet visible at the base carries the risk of the plant dying.

Therefore, the best time for hard pruning is around March, when new buds begin to appear at the base of the plant, as this is the safest time. By waiting to confirm the activity of the new buds before working, you can significantly reduce the risk of failure.

To perform hard pruning, cut the branches just above the new buds at the base of the plant. While being careful not to damage the new buds, cut back the old, woody branches. This principle of "cutting above the new buds" is the most important point in hard pruning.

Note that after hard pruning, the plant's ability to absorb water temporarily decreases due to the reduction in leaves, so be mindful to water only after the soil has dried out thoroughly to prevent over-moistening. If you keep the plant in a sunny location where it receives gentle spring light, it will encourage the growth of new buds and speed up recovery.

Pruning shears

💡 Tips on Woody Growth and Pruning by Variety

There are various lavender variety groups, and they differ in how easily they become woody and their tolerance to pruning. Knowing the characteristics of the variety you are growing will allow for more appropriate care.

English Lavender (Angustifolia group) is highly cold-tolerant and relatively resistant to hard pruning. In Japan, this group is representative when people say "lavender," and it is also famous for being cultivated in Hokkaido. Woody growth tends to progress slowly, but if you neglect annual post-bloom pruning, the shape will collapse within a few years.

French Lavender (Stoechas group) is a variety characterized by its rabbit-ear-shaped bracts. It tends to become woody faster than the English group and has a slightly lower tolerance for hard pruning. It is important to prune carefully after flowering and address the plant before woody growth begins.

Lavandin (a hybrid of the Angustifolia and Spica groups) is vigorous, tends to grow into a large plant, and is relatively strong against hard pruning. Because it easily becomes large, if you want to keep it compact, be sure to prune it back well during post-bloom pruning.

Lavender Lavandin Grosso 9cm Pot, Set of 2

Lavender Soil 10L

✨ Management Tips for Long-Term Growth

In addition to pruning, daily management determines the lifespan of lavender. Keep a few basic points in mind.

Regarding soil and drainage, lavender prefers well-draining soil. For potted plants, commercially available herb potting mix or a flower potting mix with 20-30% akadama soil or pumice mixed in is suitable. For planting in the ground, mixing magnesium lime into clay-like soil to improve drainage and soil pH (lavender prefers slightly weak alkaline) will stabilize growth.

The basic rule for watering is to "water thoroughly once dry," and over-moistening is strictly forbidden. Especially during the hot and humid summer season, be careful as overwatering can easily cause root rot and stuffiness.

Be careful not to over-fertilize. Lavender is a plant that originally prefers poor soil, and excessive fertilizer can cause it to grow leggy and lose its shape. A small amount of slow-release fertilizer applied before spring budding and after post-bloom pruning is sufficient.

If you find it difficult to get the plant through the summer, it is also effective to grow it in a pot and move it to a semi-shaded area where it will not be exposed to rain during the rainy season and summer.

📝 Summary

Woody growth in lavender can be suppressed through proper annual pruning. Make it a habit to shape the plant with post-bloom pruning, and when woody growth becomes noticeable, wait for the timing when new buds appear in spring (around March) to perform hard pruning.

Pruning is not something that "damages the plant," but rather a task to "rejuvenate the plant." By understanding the nature of lavender and continuing careful care every year, you can enjoy beautiful flowers for many years.

This article is an improved version of the original content published on "Lovely Plants (https://lovely-plants.com)," reorganized for better readability with additional useful information. Please be sure to check out the original article as well.

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