By: Jackie Carroll
Given the right conditions, rosemary plants thrive, eventually reaching heights of 6 to 8 feet (1.8-2.4 m.). They grow out as well as up, sending out stems that seem determined to explore their surroundings and invade the space of adjacent plants. If your rosemary plant has grown out of control, it’s time to take drastic action. Rejuvenation pruning of rosemary may be needed.
Gardeners are sometimes hesitant to make drastic cuts on rosemary shrubs because a few herbs with similar, woody stems don’t recover if you make severe cuts. A mature rosemary plant, however, tolerates this drastic pruning, even into the woody parts of the stem.
You can do light pruning and harvesting any time of year, but a rosemary plant responds best to hard pruning in winter when it isn’t actively growing. When pruned in winter, the plant grows back in spring looking better than ever. Read on to find out how to rejuvenate a rosemary shrub.
Note: For most people who grow rosemary, the plant will go through a cold period. It isn’t a good idea to prune any herb, rosemary or otherwise, shortly before or during cold because it will cause the plant to grow new shoots, which are very vulnerable to cold damage. In warmer areas where rosemary is more apt to grow to the size in which rejuvenation pruning is needed, the plant is not experiencing the same killing cold, so winter pruning while it’s in dormancy is best. That being said, for those of us NOT living in such areas, stick to spring pruning after the threat of frost has passed.
The first step in rejuvenating rosemary plants is to determine the size at which you want to maintain the plant. Cut the shrub back to about half of the desired size, and by the end of spring it will fill the allotted space. You can maintain the size of the shrub through summer with light pruning and harvesting.
Cutting through the thick, woody parts of the stem on a mature rosemary shrub may be too much for your hand pruners. If you find the stems hard to cut, use loppers with long handles. The length of the handles gives you more leverage and you’ll be able to make the cuts easily. When tender new shoots replace the old growth, you’ll be able to make cuts easily with hand pruners.
Don’t toss the prunings on the compost pile! Save the best tips to start new plants, and strip the needles off the remaining stems for drying. The tough stems make excellent kabob skewers.
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You may have heard the terms “rejuvenation pruning” or “renovation pruning” and wondered what it meant. What exactly is being “rejuvenated” or “renovated”?
Basically, it involves cutting a shrub right down to the ground. That’s right – just whack the whole thing down to ground level or just a little higher.
Surprisingly, shrubs that respond well to this kind of treatment will quickly send up new stems. Over the next few years, you’ll want to thin these stems to reduce crowding and maintain the size and shape of the shrub.
However, not all shrubs can tolerate this kind of pruning. Be sure that you know how a shrub will respond before you start cutting!
Rosemary is native to the rocky hillsides of the Mediterranean region, where the sandy soil drains quickly and there is a winter rainy season and dry summer. The rosemary plant can survive on as little as 12 inches of rain a year but does need occasional water. If it is watered too much or too little, the leaves die and turn brown. Soak the soil thoroughly when you water, and then allow it to dry completely before watering again. In rainy climates, plant rosemary in sandy soil to aid drainage.
Aphids, whiteflies and spittlebugs are common on rosemary. All are sap-sucking insects that do not cause much damage in small numbers but can cause leaves to yellow and die if populations are high. They can be washed off the plant with a strong stream of water if they are causing damage. Control nearby weeds, which can be alternate hosts to these insects.
Upright rosemary varieties can reach 3 to 5 feet tall in warm climates. When your area experiences the occasional freeze, an established plant is likely to survive and look as good as new in a few weeks after some trimming. After a cold snap, the tips of the rosemary turn dark brown and look dry and brittle. Leave the damaged plant parts on the bush until temperatures are consistently warm because it can protect the parts of the plant that are still healthy, farther down the plant. Cut the stems back to living wood with bypass pruners, cutting at a 45-degree angle. Trim the stems back all the way to the base of the plant if there is no live wood on the stem.
Patricia Hamilton Reed has written professionally since 1987. Reed was editor of the "Grand Ledge Independent" weekly newspaper and a Capitol Hill reporter for the national newsletter "Corporate & Foundation Grants Alert." She has a Bachelor of Arts in journalism from Michigan State University, is an avid gardener and volunteers at her local botanical garden.
This can be done as early as late winter and then through spring and summer. It’s not necessary to wait for the flowering to finish and, in fact, this is not a good idea. Pruning too late in the year might encourage new growth that will not have hardened before the first frost. In many locations, late July is a good time, and for warmer hardiness zones, you can prune in September. A general rule is to prune no later than about 4-6 weeks before the first frost.
Rosemary is very good at taking care of itself, particularly plants grown in pots. It’s not necessary to prune plants unless they are overgrown, over woody, or unless you are trying to make a hedge or prune into topiary shapes. Also, you may simply want to prune rosemary to reduce the size of the plant or to make your existing plant more productive next year.
My rosemary has quite a bit of older growth on it, so I want to prune it now so that the time I have left will give me some fresher tips to use in Thanksgiving cooking. Rosemary grows for me pretty much all year round, here in zone 7b.
Before you start the job of pruning rosemary, be sure that your garden shears are nice and sharp. Dirty shears with blunt tips will mean that your cuts are ragged, which can encourage disease and pest problems. All garden tools need to be tended to this time of the year. Be sure to check out my general tips for winterizing your garden tools, as well.
General Pruning. To prune rosemary, clip off the faded flowers, if any. You can preserve the flowers with Borax for use in dried flower arrangements, craft projects or potpourri. Use a good pair of pruning shears to trim back just below the flower area. If the plant is not flowering, just snip off the top few inches of the stems, being careful not to move too far into the old wood.
If your aim is a bushy plant, just remove about 1 – 2 inches of all of the branches. This encourages each tip to split into two and will give you a nice bushy looking plant before you know it.
Hard Pruning. Since rosemary is a perennial,if it is grown freely in the garden can get to heights of 6-8 feet! Any plant this size will get woody and unkempt looking if not pruned.
If you decide to do more of a hard pruning, earlier in the year, ratcheting pruners will make cutting the old wood easier, but never cut more than 1/3 of the plant or you may kill it. With old wood, a good rule of thumb is one branch out of three. Then, 6-8 weeks later, as the new growth is growing vigorously, you can cut back another woody branch and so on. At all costs, don’t cut all the old wood off at once.
Rosemary is a perennial herb, so it will continue growing year after year in containers. This can result in pot bound plants.
A pot bound rosemary plant will produce less and less new growth and get quite woody. Re-pot the plant into a larger pot, if you can. If not, remove the plant from the container and carefully prune the roots back and bit and add a fresh layer of soil. I find that I can grow rosemary for several years in a large pot before it needs this step..
Rosemary can be easily dried for use in recipes during the winter and, like most herbs, can be preserved many other ways. Rosemary oil and rosemary herb butter are just a few ideas.
You can also root the cuttings of newer shoots of rosemary to get more plants for free. Either place the springs in water to grow roots and plant them in soil, or use a root powder on the tips and plant them directly into soil. Before you know it, you’ll have a new plant. Rosemary makes a great indoor plant to grow on your kitchen counter near a sunny window.
These tips for pruning rosemary bushes are easy to do but important in the overall look and health of the plant. Knowing how to prune rosemary plants will make for a happy plant that gives you sprigs of lovely flavor for cooking.
Delicious chives can be rejuvenated to increase their cropping time. We show you how.
Published: Tuesday, 14 May, 2019 at 3:00 pm
Plant is not at its best in January
Plant is not at its best in February
Plant is not at its best in March
Plant is not at its best in April
Plant is at its best in May
Plant is at its best in June
Plant is not at its best in July
Plant is not at its best in August
Plant is not at its best in September
Plant is not at its best in October
Plant is not at its best in November
Plant is not at its best in December
Do not To do in September
Growing your own chives is easy, and provides a steady crop for use in salads, sandwiches and dips.
Chives grow very well in most conditions, withstanding poor soil, frost, partial shade and full sun. They require very little maintenance, but give them the occasional chop, and you’ll be harvesting leaves and flowers right through the summer.