This article is all about Russian sage pruning, including when, why, and how. Learning how to cut back Russian sage properly is essential for plant health and maintaining the ideal growth habit of this hardy perennial. Read on to learn why millions of gardeners worldwide grow this beautiful flowering plant and how to trim it properly. You’ll also find general plant care tips for this popular perennial.
Why grow Russian sage
Russian sage (Perovskia atriplicifolia) is one of those perennials that ticks all the boxes. It is one tough – and beautiful – cookie. I have four of them in my own garden and have found few other plants that perform as well in the heat of summer. A native of Central Asia and a great choice for gardeners from USDA hardiness zone 4 to zone 9, Russian sage is a woody perennial that survives winters down to minus 20°F (and perhaps even lower if the soil is not water-logged). But its hardiness isn’t its only worthwhile attribute. This drought-tolerant member of the mint family grows to a height of 2-3 feet and is covered with elongated spires of lavender-purple flowers from late spring through fall, making a gorgeous show of non-stop blooms.
Prized for its low-maintenance by humans, Perovskia is also prized for its nectar by bees and butterflies. Because it forms woody stems within a single growing season, it’s almost more like a shrub than an herbaceous perennial. It is a great choice if you are plagued by deer or rabbits as neither animal eats Russian sage. The small hairs on the foliage coupled with the leaves’ strong fragrance, make Russian sage among the most rabbit- and deer-resistant perennials out there.
Is Russian sage pruning necessary?
While Russian sage plants require very little care, a yearly pruning is essential for their upkeep. The panicles of blooms require strong, sturdy stems to stay upright, and if you don’t prune the plants properly and at the proper time, this tough plant tends to flop over when in bloom. Properly pruning Russian sage translates to thicker, stronger stems that better support the flowers. Failure to prune Perovskia appropriately translates to weak, slender stems that are too long and too wimpy to hold each blue spire of blooms upright.
It’s also important to note that Russian sage prefers dry soil and full sun. Opt for locations with well-drained soils, such as at the top of retaining walls or the top of slopes. Avoid low-lying sites and water-logged soils, particularly in winter, as wet soil causes root rot. Russian sage is a good choice for hot, drought-prone gardens. Three of mine are in the sloped perennial bed right next to my hot asphalt driveway. They are thriving. They are also pretty much the only plant out there that I DON’T have to spray with my most-trusted deer repellent every three weeks.
The best time for Russian sage pruning
Very early spring or late winter are the ideal times for pruning Russian sage plants. The best time is anywhere from 6 to 10 weeks before your last expected spring frost. Here in my Pennsylvania garden, I prune my Russian sage back around mid-March (8 weeks before my average last frost date of May 15th). Early spring pruning like this removes last season’s branches before any new leaves emerge from the stem, lessening the chance of harming any freshly emerging foliage when cutting the plants back.
How far back to cut Perovskia
Here’s where most people go wrong when it comes to pruning Russian sage. For some reason, gardeners think less pruning is better, when – at least with Russian sage and other woody perennials like butterfly bushes and Caryopteris – the opposite is true. Heavy pruning is necessary to encourage sturdy future growth.
Use a pair of sharp pruning shears, like my beloved Felcos, to remove all of the stems on your Russian sage plant down to a height of 6 inches. Cut each stem off just above a pair of side buds. The buds are easy to spot along the stems. They sit opposite each other and are white to gray in color. The reason you prune to just above a pair of lateral buds is because, when the growing season arrives, those two buds will develop into two thick and sturdy branches. They will eventually go on to produce the coming year’s blooms.
Occasionally, in very cold growing zones, Russian sage plants die all the way back to the ground because the leaf buds freeze out. When this happens, new growth emerges in the spring from beneath the ground, rather than from the side buds. Sometimes this growth from the ground occurs later than usual and gardeners may think the plant is dead. If that happens, there’s no need to worry. Give the plant some time. It should develop new growth, if a little later than usual, and go on to flower as normal.
Watch me cut back my Russian sage in this video:
What happens if you don’t prune Russian sage
You may think that you shouldn’t cut the plants back so far, especially if the branches are still green inside (which means they are living tissue). But that would be a mistake. Not only would you have new growth mingled with dead branches, but that new growth would be weak and unable to support the weight of the blooms.
That being said, Russian sage stems are a beautiful sight in the winter landscape. Always allow them to remain in the garden through the winter and do your pruning in the early spring.
Pinching Russian sage mid-season
One of the coolest ways to prolong the bloom time of Russian sage is through the practice of pinching. While this is more of an advanced gardening practice, it’s one worth learning. Like phlox, bee balm, chrysanthemums, and certain other perennials, Perovskia plants can benefit from a pinch mid-season. Pinching Russian sage stems back to half of their total height in early to mid June results in doubling the number of flowers, delaying the bloom time by several weeks, and creating more compact growth habit.
While the process of pinching Russian sage may seem scary, know that it isn’t essential. I pinch back half of the stems on each of my plants, rather than pinching all of them. This results in a super-long bloom time since the branches that are left unpinched start flowering first. They are then followed by the flowers from the pinched stems several weeks later. I get months of blooms instead of weeks when I pinch only half of the stems. To pinch, use your thumb and forefinger to literally pinch off half of each stem’s height. You can also use a flower snip or a pair of pruners for the job.
While Perovskia is generally trouble-free, there are a few issues that could crop up for you.
- Since these plants prefer dry conditions and well-draining soil, very wet winters and springs can result in plant death. If you have heavy clay soil, it’s essential you opt for a site with good drainage.
- Properly pruned Russian sage seldom requires support. However, older cultivars tend to be a little more floppy and may require stakes (or my favorite flower cages) to keep the stems upright. Newer cultivar selections, such as ‘Little Spires’, ‘Denim ‘n Lace’, and ‘Blue Jean Baby’, have been bred for a shorter stature.
- While few garden pests bother Perovskia, one little bugger called the four-lined plant bug loves to suck juices from the foliage. If you find leaves with brown, perfectly round pockmarks on them, here’s what to do about four-lined plant bugs.
Additional tips for growing Russian sage
- These perennial plants require very little care. Mulch them with a light layer of compost yearly to provide nutrients to support their growth and flowering.
- Plant Russian sage with other complimentary perennials. The fine texture of their foliage looks great with Echinaceas, Salvia, daylilies, Shasta daisies, Rudbeckias, and other plants that thrive in similar growing conditions.
- Applying nitrogen-rich fertilizer to Russian sage plants results in soft, floppy growth. No need to add supplemental fertilizer; amending with compost is all that’s necessary.
- Remember, pollinators adore this plant, and they will be actively feeding on the flower nectar for much of the summer. Avoid using any pesticides (organic or synthetic) near or on the plant when pollinators are active.
- The ideal soil pH for Perovskia is slightly alkaline (7.2-8.0), though my soil is slightly acidic and I have no problem growing this beauty.
Now that you know the essentials of pruning Russian sage, you’re set for success. This yearly practice only takes a few moments of your time but is critical to the health of the plant. Time your trimming appropriately, remove all stems down to a height of 6 inches, and you’ll be enjoying the gorgeous flower color and wispy texture and growth for many years to come.
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