Pine-like Russian sage (Perovskia atriplicifolia) grows on the ground and has lavender flowers that grow on 3- to 5-foot-tall stalks from summer to fall. They are hardy in U. S. Department of Agriculture zones 5 to 9 and are excellent landscape plants, including in rock gardens. However, Russian sage is sometimes aggressive and can grow outside its intended space. You can get rid of Russian sage in your garden by pulling it out by hand or killing it with a flower killer.
Two days before you remove the Russian sage by hand, water the soil with about 1 to 2 inches of water. Slightly moist soil is easier to dig in than extremely dry soil. To get all the roots, dig around clumps of Russian sage and go about 8 to 10 inches deep. Adjust the digging as necessary to remove all the roots. Discard dug up Russian sage plants in the trash rather than the compost pile to prevent re-infestation.
Apply a systematic herbicide on the Russian sage as an alternative to removing it manually. According to Ohio State University, the herbicide with the active ingredient prodiamine is effective in killing Russian sage. Apply directly to the leaves on a calm day. Read the herbicides usage label and use accordingly. It is illegal to use herbicides in any other manner.
Remove or apply the herbicide continually whenever Russian sage sprouts grow back. It may take several months of persistent removal to kill the plants completely.
Russian sage (Perovskia atriplicifolia) is a popular ornamental plant grown for its spiky lavender-blue flower spikes and silver foliage. While beautiful, this hardy perennial can spread aggressively and become weedy. If you have Russian sage growing where you don’t want it, getting rid of it for good can take some persistence. Here’s a complete guide to eradicating Russian sage using both natural and chemical methods.
Understanding Russian Sage
Russian sage is native to Central Asia but has become a mainstay in gardens across North America and Europe, Below are some key facts about this plant
- Perennial growing 2-5 feet tall and wide
- Flowers on tall spikes from midsummer to fall
- Leaves are silver and finely dissected
- Spreads by rhizomes and self-seeding
- Tolerates drought, heat, cool weather, and poor soil
- Deer and rabbit resistant
Due to its vigor and adaptability, Russian sage can escape gardens and take over open areas. It’s considered an invasive exotic plant in some regions. Before removing Russian sage, make sure it’s not native to your area.
Manual Removal
Manually digging up Russian sage is straightforward but labor intensive for large infestations Follow these steps
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Water the area thoroughly a day before to loosen the soil.
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Use a spade or garden fork to dig around and under each plant. Aim to remove as much of the root system as possible.
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Shake or hose off excess soil and dispose of the plants in the trash or a hot compost pile.
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Be diligent about removing every piece of root and rhizome. Even tiny fragments left behind can resprout.
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After digging, cover the area with cardboard or a dark tarp to inhibit regrowth.
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Monitor for new seedlings and resprouts. Pull them quickly before they establish deep roots.
Manual removal works best on small infestations and is safest for the environment. Just be ready to keep monitoring and pulling for resprouts.
Smothering
Smothering Russian sage with mulch or other covering can control it without chemicals. Use materials like:
- Cardboard sheets
- Landscaping fabric
- Tarps or weed barriers
- Wood chips, bark, or gravel mulch
Cover the plants with 4-6 inches of overlapping material. The covering blocks light and prevents photosynthesis, eventually killing the Russian sage. Reapply more material as needed.
For permanent control, continue covering the area for at least one growing season. Monitor for any new growth around the edges. Combine with manual digging for best results.
Herbicides
Non-selective systemic herbicides that move through the whole plant are most effective on Russian sage. Glyphosate products like Roundup are commonly used. Other options include horticultural vinegar and natural acids like caprylic acid.
When using any herbicide:
- Read and follow label directions carefully
- Avoid contact with desired plants
- Apply on a calm day to avoid drift
- Spray late in the day to avoid rapid drying
- Wear protective clothing and eyewear
For Russian sage, the best time to spray is mid to late summer when the plants are fully leafed out and actively growing. Spray the entire plant for full coverage:
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Cut plants back to 6 inches and let regrow before spraying for better herbicide uptake.
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Use a small spray bottle for scattered plants or a pump sprayer for large areas.
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Wet the foliage thoroughly but avoid runoff into soil.
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It may take several treatments over one or more years to fully kill the roots. Monitor for any regrowth.
While effective, herbicides have drawbacks like toxicity to pets, beneficial insects, and other plants. Consider them as a last resort if manual methods fail.
Prevention
An ounce of prevention is worth a pound of Russian sage removal. Here are some tips:
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Research plants thoroughly before planting and avoid aggressive spreaders.
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Remove flowers before they set seed to prevent reseeding.
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Don’t dump garden waste containing Russian sage in natural areas.
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Plant in containers or beds surrounded by concrete or plastic edging.
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Surround plantings with a “root barrier” made from thick plastic, metal, or concrete.
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Pull out and destroy any unwanted seedlings when they first appear.
Catching Russian sage early makes removal much easier. Stay observant and take action at the first sign of spreading to keep it under control.
When to Call a Professional
Extensive Russian sage growth may require professional help. A landscaper can access specialized tools and chemicals not available to homeowners. They can also properly dispose of the toxic plant waste.
Signs it’s time to call in a pro:
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Infestation covers over half an acre.
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Digging up the plants would severely disturb the landscape.
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Removal requires permits or environmental precautions.
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The infestation borders sensitive habitats like streams or prairies.
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You are unable to fully remove the plants after several control attempts.
Don’t allow Russian sage to take over your landscape. With persistence using cultural, mechanical, or chemical control methods, you can get rid of this aggressive perennial for good.
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How to Kill Russian Sage
FAQ
How to stop Russian sage from spreading?
Does Russian sage have deep roots?
How invasive is Russian sage?
What happens if I trim Russian sage?
How to get rid of Russian sage?
However, Russian sage is sometimes aggressive and can grow outside its intended space. If you want to get rid of the Russian sage in your garden, you can remove it manually or kill it with a chemical herbicide. Water the soil with approximately 1 to 2 inches of soil two days before removing the Russian sage manually.
How do you take care of Russian sage?
Water the soil with approximately 1 to 2 inches of soil two days before removing the Russian sage manually. Slightly moist soil is easier to dig in than extremely dry soil. Dig around clumps of Russian sage and dig about 8 to 10 inches deep to get all the roots. Adjust the digging as necessary to remove all the roots.
Should I cut back Russian sage?
If your plants tend to flop during the summer you can cut them a second time. Prune the plants back halfway once they reach 12 inches. Those considering adding Russian sage to their gardens may want to try Little Spires, a shorter (four foot tall) cultivar that is less prone to flopping.
Should Russian sage be pruned every year?
Many gardeners, even in regions where the plant is evergreen, choose to severely prune Russian sage annually. The argument for pruning is that the plant will grow to be bushier the next season. And in cold-winter zones where the plant dies back each year, hard pruning is mandatory.
Can Russian sage grow in dry soil?
They prefer alkaline soils of pH 7 and greater but can tolerate a wide range of soil pH (6.5–8.0). New transplants need regular watering, but once established, Russian sage is very drought-tolerant. It likes medium to dry soil and will do fine in hot, dry areas of your yard or garden.
How to propagate Russian sage?
Russian sage can be propagated by division every three years in the spring season or fall. To do this, cut down the stems to approximately 6 to 8 inches high with garden trimmers when the plant is not in active bloom and the buds are dry. Russian sage is not in active bloom when the buds are dry, even though it may still look active.