Sage in winter: is sage winter hardy?
Common sage (Salvia officinalis) is a wonderfully hardy herb. But with over 1000 species in the Salvia genus, knowing how and when to protect other varieties can be confusing. Learn how to overwinter your favourite salvias.
The salvias are part of the mint family (Lamiaceae) and offer a spectacular range of ornamental and culinary species. They include annual, herbaceous perennial, tender perennial and shrubby varieties of sage that require various levels of care when frost threatens. Read on to find out which salvias are most frost tolerant and how to overwinter the less cold hardy salvias.
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Is sage winter hardy?
Whether your sage is hardy depends on the local climate. However, there are many frost tolerant sage varieties that are easy to grow and rarely require protection. Some extremely cold hardy sages include:
- Common sage (Salvia Officinalis): hardy to -15 ˚C. Note that the cultivars of the species, such as ‘Tricolor’ and ‘Purpurascens’, are generally less hardy
- Clary sage (Salvia sclarea): hardy to -15 ˚C
- Sticky clary (Salvia glutinosa): hardy to -20 ˚C
- Meadow clary (Salvia pratensis): hardy to <-20 ˚C
- Balkan clary ‘Porzellan’ (Salvia nemorosa ‘Porzellan’): hardy to <-20 ˚C
- Wood sage ‘Crystal Blue’ (Salvia nemorosa ‘Crystal Blue’): hardy to <-20 ˚C
- Lyre-leaf sage ‘Purple Knockout’ (Salvia lyrata ‘Purple Knockout’): hardy to <-20 ˚C
Tip: find out exactly how cold hardy your sage variety is by checking out its ‘hardiness rating’. The UK scale ranges from H1a (>15 ˚C) to H7 (<-20 ˚C). Your plant supplier or a simple internet search can tell you where your salvia lies on the scale.
These impressively hardy sage varieties have several sensitive cousins that need frost protection over winter. Pineapple sage (Salvia elegans), gentian sage (Salvia patens) and anise-scented sage (Salvia guaranitica) are all popular varieties that need to be overwintered. Keep reading to learn how best to overwinter your cold sensitive sage plants.
How to overwinter sage?
How to overwinter sage depends on whether you are growing it in beds or in pots. In either case, propagate new plants by taking cuttings from your salvias in August. This way, any winter losses are easily replaceable. If you are growing in beds, do not prune your sage plants beyond late summer.
Overwintering sage in beds
Frost damage to freshly cut tissue makes it harder to protect your salvia over winter. There are several strategies for overwintering sage grown in beds:
- Mulch your plants to protect the roots, crowns and emerging shoots. Use a 10cm layer of well-rotted garden compost or a general-purpose compost such as our Plantura Organic All Purpose Compost. Its open structure helps prevent waterlogging and provides a moderate dose of nutrients sufficient to sustain your overwintering sage.
- Secure a layer of horticultural fleece around the plant before the first frost. Remove it on mild dry days to allow air to circulate and prevent disease.
- Watering sage in the bed over winter is rarely necessary; if it is, do it sparingly, as wet roots make sage vulnerable.
- In cold regions, lift half-hardy and tender salvias from the bed and transplant to pots. Place the pots in a bright, cool but not frosty location with low humidity such as a greenhouse or cold frame. Add a layer of horticultural fleece for extra protection if temperatures plummet.
- Lifted plants kept in an unheated greenhouse or conservatory must be kept almost dry in the coldest, darkest months.
- Replant the sage in the spring when risk of frost has passed, but first acclimatise it gradually to outdoor conditions over several weeks. Move it back indoors at night and be ready with a layer of fleece if temperatures drop once it is replanted.
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Overwintering sage in pots
If you grow it in pots, overwintering your sage indoors is very straightforward providing you have a bit of space and follow these simple techniques:
- Place pots in a right and dry location by a window or in a conservatory. A temperature between 15 and 21 ˚C is ideal.
- Plants kept near radiators dry out more quickly, so keep an eye on soil moisture levels when the heating is on.
- Do not allow the soil to become waterlogged.
- Mulch the soil surface with a general-purpose compost.
- If you do not have space indoors, keep pots outdoors in a sheltered area and avoid frost pockets. Protect from heavy rain and snow if possible. Outdoor salvia in pots need more protection than those in beds.
- Wrap the outdoor pots gently but securely in a layer of bubble wrap, remembering to ventilate them occasionally on milder days.
- Secure a double layer of hessian sacking or bubble wrap around the pot to protect the roots from frost.
If you are new to the world of salvias, why not start by growing the popular garden herb, common sage? Read our dedicated article on sage care to learn more about this low maintenance salvia.
