Why Subshrubs Like Lavender and Rosemary are Hard to Divide

Did you know not all plants that come back year after year can be easily divided? Subshrubs like lavender and rosemary are harder to divide than you may think and I’ll tell you why.

It’s important to prevent plants that share garden space from overcrowding one another. I usually start dividing and transplanting overgrown perennials in April.

But did you know that there are certain plants that are hard to divide because they are subshrubs?

Subshrubs are bushes that have a woody base, like a tree, and whose soft stems die back during the winter.

Examples of Subshrubs

• Lavender
• Rosemary
• Periwinkle
• Thyme
• Sage
• Heather

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Why are Subshrubs like Lavender and Rosemary are Hard to Divide?

Subshrubs have a single stem and root system which makes them more difficult to divide than other perennials.

Because the top of the plant does not harden off before winter like other shrubs, true dormancy is never reached. Because of this, the top portion of a subshrub is susceptible to frost damage.

The amount of damage depends on how cold it gets and the amount of snow that has fallen in your area.

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Subshrubs Can Get Leggy

Subshrubs are woody at the bottom and develop new buds higher up the plant each year.

As they grow taller they get extremely leggy with most of the green part of the plant above the dead-looking stems.

By pruning your subshrubs at least once a year, usually in late spring or early summer, you can help to prevent the plant from getting too leggy.

It’s important not to prune back subshrubs such as lavender until you see new growth. This is because it’s hard to know how much a plant has been damaged over the winter until you start seeing new buds form.

It’s recommended not to remove more than one-third of a plant’s total growth when pruning. However, rosemary can handle pruning better than other subshrubs so it will most likely grow back even after being cut back aggressively.

I hope I’ve clarified some questions you may have about what a subshrub is and why plants like lavender and rosemary are harder to divide.

If you have any questions or additional suggestions, please share them in the comments below. And be sure to share this blog post link with anyone who may find these gardening tips useful.

Until next time,

Happy Gardening!

I’m a self-taught hobby gardener. Everything I share on my blog is my opinion and what has worked for me.

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