The lovely fragrance of Salvia is bolstered by their wonderful flowers in a range of vibrant colours. Find out the answers to Google’s most asked Salvia questions in this blog.
Where are Salvias native to?
Salvias are native worldwide. Plants that have this trait are known as ‘Cosmopolitan’.
Are Salvias annuals, biennials, or perennials?
They can be annual, biennial or perennial. There are many different varieties of Salvia which grow and live for different periods and under various conditions.
Bedding salvias can be either annuals or biennials, which will last between one and two years. Painted sage is a lovely annual option which is great for using as cut flowers, or perhaps Salvia argentea, ‘Silver sage’, which is a wonderful biennial option.
Border salvias can be anything from frost-hardy herbaceous perennials to deciduous shrubby salvias, and even semi-evergreen shrubs. Salvia ’Hot Lips’ is a very popular choice.
Tender Salvias need winter protection unless you live in a particularly mild area of the UK. You just need to dig these up and bring them indoors over winter to keep them protected from the frosts.
Finally, there are culinary salvias, which include sage, and recently rosemary plants too. These salvias are evergreens and so they have ornamental value too.
Which garden style are they best suited for?
Salvias are bright and impactful, and their tall flowering spikes are lovely in either Mediterranean or Cottage-style gardens.
How do you grow Salvias from seed?
This varies depending on the type of salvia you are growing.
Annual and bedding salvias can be sown under cover in shallow trays filled with peat-free compost between March and April, or directly into the soil in their final position once any risk of frost has passed.
If you have chosen to grow biennial salvias from seed, you can sow them into shallow trays in the summer. Once they have germinated, simply prick them out and grow them on in individual pots or plug trays.
Do so in an unheated greenhouse over winter, before being planted out the following spring, once there is no risk of frost.
Border and tender salvia seeds can be collected once ripened between summer and autumn, to be stored over winter before sowing in trays in the following spring.
Due to cross-pollination, it is very likely that your new salvias will not be identical to the parent plant.
Are Salvias easy to grow?
Yes, they are, and they are also particularly fuss-free when grown from seed. Make sure you know which type you have, and they should grow well with little hassle.
Where do they grow best?
Generally, all salvias will grow well in moist, free-draining soil, in a sunny spot, with shelter from the wind.
How do you grow Salvias?
Before planting, if you have heavier soil like clay, it is worth digging in some horticultural grit to improve the drainage.
The general planting requirements for salvias stay the same. Dig a hole slightly bigger than the container your plant came in. Then plant the salvia at the same depth as the original pot. Backfill it with soil, firm in, and water well.
For biennial and perennial salvias, make sure you water them regularly during any prolonged dry spells in their first year. This will help them to establish.
Salvias aren’t hungry plants so using fertiliser isn’t essential when planted in a border..
If you’re growing salvias in containers, however, then some potassium-rich feed is beneficial once a month during the growing season.
How long do they live for?
Depending on the type of salvia you have, this could be anything from 1 year to over 3 years for perennial and shrubby varieties.
How big do they grow?
A compact variety which is suitable for growing in beds will be about 20 cm tall, like Salvia ‘Red Arrow’. Though border types such as Salvia uliginosa can reach about 2 metres in height.
How long do Salvias flower for?
Salvias, depending on the variety, tend to flower between June and October every year.
Will Salvias flower twice?
Perennial salvias can flower more than once, yes. If left alone, you will get no more than 2 flowering periods, but if you deadhead them, you could increase this to up to 4 times.
Are Salvias good for bees?
All salvia varieties produce flowers which are beloved by pollinators, particularly bees.
Are they frost hardy?
Some perennial types are frost hardy, whilst annual types are unlikely to cope well with the colder weather.
What colours do Salvias come in?
Salvia comes in an array of colours. With shades of purple and lavender through to reds, pinks, magentas, and blues.
Do they need a lot of water?
If your salvias are growing in containers, yes, make sure you check the soil often as you are the custodian of your pot-grown plants – their supply of water is limited.
For salvias grown in the ground, they are pretty drought-tolerant, so provided there is regular rainfall, should only need watering during particularly dry periods.
Do they need staking?
No, Salvias are pretty reliable for staying upright without support. If it is slightly leggy and struggling to hold the weight of the flowers, canes can be inserted to give them a helping hand, or they can be cut down to grow again stronger.
Do Salvias make good cut flowers?
Yes, with their long stems make a wonderful tall feature in cut flower displays.
Do Salvias need deadheading?
Yes, salvias benefit from being deadheaded. Cutting down the spent flowers will give your salvia plant more energy to produce more blooms throughout their flowering period.
What do you plant with them?
When to cut back Salvias?
Bedding Salvias only need deadheading to encourage flowers, and the same with annual and biennial varieties.
Herbaceous salvias can be cut back in mid-summer to nearly ground level to encourage more flowers, and again in autumn in milder locations.
For semi-evergreen shrubby varieties, cut the woody stems back in mid-spring to encourage new growth. If flowering stops around July, another light pruning should give them the boost to flower again in late summer.
Deciduous shrubby salvias benefit from hard pruning to 5-10cm tall in mid-spring.
Try to avoid cutting salvias back in autumn, as the foliage can give them valuable protection from winter frosts.
How to divide Salvias?
Herbaceous border salvias can be divided in spring once they have become established clumps. Lift them gently with a garden fork, and remove any excess soil.
Gently pull the clumps apart, until you have smaller clumps which can be replanted.
When do they start to grow back?
You will start to see them emerging again in early spring.
Do Salvias self-seed?
Border and tender salvias may self-seed if their seeds ripen in the summer and autumn and are allowed to fall around the parent plant.
Keep an eye on these seedlings that they don’t crowd the parent plant too much, creating competition for space.
What are the common problems with Salvias and how do I fix them?
There are no particularly severe problems with salvias, but here are a few diseases you may need to be aware of:
Powdery Mildew
This is most likely to be seen amongst drought-stressed salvias. It can be identified by the spreading of white patches on leaves and flowers. By ensuring you add plenty of organic matter to the soil ahead of planting, and mulching and watering during dry spells, you should find the problem eases.
Grey Mould
Otherwise known as Botrytis, this is likely to develop in cool and damp conditions. Be particularly aware of this amongst overwintering salvias, as they can be in the perfect conditions for Grey Mould. You will notice this as shrivelling above-ground parts of the plant, with small black seed-like structures appearing on any material that is infected.
To treat this, make sure you remove any dead and dying plant materials, and reduce humidity with ventilation.
How do I stop slugs and snails from eating my Salvias?
I’ve made a video on organic methods to stop slugs and snails – and you can watch that here.
What are the common pests for Salvias?
Aphids
You are more likely to see these on areas of new growth on your salvias. These pests tend to do very little damage, so leave them if you can tolerate them.
Capsid Bugs
These are members of a tree bug family, of which there are over 200 species in Britain. They leave tiny holes in the leaves of salvias, meaning the leaves can be left in a lace-like tattered state. Check on your plants regularly, and during the winter, remove dead vegetation as these may have become overwintering sites for the insects. Tolerate the damage if you can, and encourage predators like birds, hedgehogs, and ground beetles into the garden to manage the problem for you.
Whitefly & Sage Leafhoppers
Generally, these insects will only be an issue if your salvias are growing in sheltered spots. You may notice a speckled appearance on the undersides of leaves where these insects feed from. Sometimes, sticky yellow sheets can be enough of a deterrent to control these pests.
Otherwise, these plants don’t tend to cause significant enough damage to affect the growth of the plant, so encouraging their natural predators such as birds, ladybirds, wasps and ground beetles should be a good control method.
Glasshouse Red Spider Mites
You’re most likely to notice these in your garden during particularly dry and hot periods, particularly if kept in greenhouses, and symptoms include a fine mottling on the top of the leaf’s surface. If you have a particularly heavy infection, you might notice a silk webbing on the plants. If your plants have been badly damaged, they may struggle to recover.
Creating an environment of high humidity can go some way to reduce the risk, but severely infected plants should be disposed of to avoid spreading to other plants. Clean out your empty greenhouses or glasshouses thoroughly, including a glasshouse disinfectant if you have had a severe case of glasshouse red spider mites.
Slugs & Snails
A common garden pest, you should only find you need to be particularly wary of slugs and snails around your salvias when they are emerging as shoots in the spring. Otherwise, they are unlikely to cause significant damage.
Are they deer-resistant?
Yes, Salvias are deer resistant. Deer tend to keep their distance, because they aren’t particularly fond of the smell, alongside other strong smelling herbaceous plants like lavender.
Why are my Salvias drooping?
This could be a case of either underwatering or overwatering. As drought-tolerant plants, it is more likely a case of the latter, but just ensure you are checking the soil before watering, to ensure you are giving it the treatment it needs.
Why are my Salvias dying?
There is a decent chance overwatering may be the cause of this for all salvia varieties. Particularly for perennial types, they may have struggled to recover from the cold and wet conditions in winter. Ensure your salvias are in free-draining soil, and that you check before watering.
Aside from this, salvias tend to be trouble-free, so make sure you check whether any of the pests mentioned might be causing trouble.
Are they poisonous to humans?
Salvias are generally safe for humans to ingest. Don’t forget, Sage and Rosemary are both within the Salvia family, and they are delicious features of cosy homemade meals.
Ornamental varieties are not known to be toxic but aren’t likely to taste very nice.
The lovely pompom blooms of Alliums create wonderful interest in garden borders. If you have any questions about this or any other plants you want me to do a video on, please subscribe to my YouTube channel and leave a comment below one of my Google Questions videos.
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David Domoney is a Chartered Horticulturalist, Broadcaster, and Author. David has worked with a number of the UK’s leading garden retailers as a plant buyer and strategic consultant. With more than 30 years experience, in horticulture, David is as passionate about plants now as he was when he bought his first plant at a village fete.
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