How to Determine Whether to Keep Hardy Perennials in Your Garden

Reader Contribution by The Thyme Garden Herb Company
Published on March 31, 2014

It is officially spring! The seed and plant catalogs have been rolling in for months, making their way into homes covered in snow and ice. But with the daffodils popping, the swallows returning, and all the other tell-tale harbingers of the new season arriving, it feels like time to dust off those catalogs and get down to planning the 2014 garden. Before getting all crazy about new plantings, it’s a good idea to take stock of what survived and what needs to be repurposed into compost.

Out here in Oregon, we had one of the harshest winters on recent record. As a result, many of our normally hardy perennial herbs didn’t overwinter. One of the most frequently asked questions I’ve been getting this year is “is my rosemary (or lavender, sage, or thyme) dead?” Sadly, much of the time I’ve had to answer yes. I’d like to share a few basic ways to determine the course of action for these four herbs that can be applied to other (usually) hardy perennials as well.

Rosemary

Rosemary doesn’t like to have its root zone saturated with water. Wet winters with extended periods of standing water will kill your rosemary quickly. Likewise, heavy snow will snap branches and freezing conditions will kill the tender growing tips. Sadly, rosemary tends to go through a long, drawn out death. It’s basically the same demise as a Christmas Tree that has been cut: the root system has died, but the plant stays green for a while, then loses some leaves, then loses some of its shine and luster, and finally ends up a fire hazard.

When to prune.If just the tips of the plant are brown and the rest of the plant appears green and vibrant, give the plant a chance. It’s likely that your plant suffered from frost damage. Prune off any dead sections, keeping in mind the end result of your pruning, and wait and see. It is also possible that the roots are dying and the energy is retreating from the tips first.

When to yank. If your plant has an overall dull appearance (ie the leaves are still greenish but appear sort of cloudy and maybe even a little bit crunchy and can be stripped from the stem easily), it is time to yank it. Another way to check if the plant has life coursing through it or not is to take a sharp fingernail or knife and strip away part of the outer bark on the stem. If you see green in there, there is life. If you see nothing but brown, that section is dead. You can also study a cross-section of the stem, looking for a green living tissue. Here’s the deal with rosemary, in my honest opinion, it needs to be replaced every now and then. It’s hard to say goodbye to an old garden friend, and rosemary is my favorite herb, but it gets very woody and scraggly with many pruning’s and it is best to just pop in a new one periodically. It also gives you a chance to try new varieties.

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