Gadenin日本語Get the appThe shape of the year
Salvias ask very little across most of the season, but the few jobs they do need are strongly tied to a moment rather than spread out. Miss the spring cutback and the plant flowers over a mess of last year's dead stems. Miss the midsummer shear and you get one flush instead of two. Miss the autumn cuttings and a cold wet winter can cost you the plant.
The table below is the whole year in one place. It is written in seasons rather than dates so that it reads the same in either hemisphere, and the triggers are things you can see on the plant rather than points on a calendar.
| Season | Hardy border kinds | Tender shrubby kinds | Trigger to watch for |
|---|---|---|---|
| Late winter | Leave the dead stems standing | Keep cool, dry and frost free; no pruning | Nothing yet; resist the urge to tidy |
| Early spring | Cut last year's stems to the crown; divide every three or four years | Tidy dead tips only, once new buds swell on the stems | New shoots visible at the base |
| Mid spring | Protect emerging shoots from slugs; feed lightly if the soil is poor | Harden off and plant out overwintered young plants | Shoots two inches (5 cm) tall |
| Late spring | Stake tall kinds now, before they need it | Pinch tips of young plants to force branching | Plant reaching a third of its final height |
| Early summer | First flush of spikes; water new plantings only | Flowering starts and does not stop | First spikes coloring |
| Midsummer | Shear back by a third as the flush finishes | Shorten individual straggly stems as needed | Two thirds of the spikes gone over |
| Late summer | Second flush; deadhead spent spikes | Take cuttings if you want spring plants in flower sooner | Regrowth flowering three weeks after the cut |
| Early autumn | Stop deadheading; let the last spikes stand | Take insurance cuttings before the first frost | Nights cooling but the plant still in growth |
| Late autumn | Leave everything standing; clear mulch away from crowns | Move containers under cover; mulch crowns in the ground | First frost forecast |
| Winter | Nothing | Check overwintered plants for whitefly; water sparingly | Compost only just damp, never wet |
Spring: cut back, divide, and watch for slugs
The season opens with the cutback that should not have happened in autumn. Once you can see new shoots at the base of a hardy border salvia, cut last year's dead stems down to just above the crown. They snap off cleanly at this point, which is why waiting is easier than cutting them green in autumn, and the standing stems have sheltered the crown through the coldest weeks.
This is also the moment to divide any clump that has gone bare in the middle, and to move any plant that flopped or flowered badly last year because of shade. Both jobs go far better in spring than at any other time, because the plant has a full growing season ahead of it to re-establish.
For the tender shrubby kinds, wait longer. Do nothing until you can see buds swelling along the woody stems, then cut back to the highest live growth. Cutting a shrubby salvia early, before the extent of the winter damage is clear, means cutting into wood that would have recovered.
The three weeks after the shoots emerge are the only period when slugs are a serious threat. Clear the old debris away from the crowns, protect the new growth, and stop worrying about it once the shoots are six inches (15 cm) tall.
Summer: one flush, one cut, then a second flush
The first flush on the hardy kinds arrives in early summer and runs for several weeks. Do nothing during it except enjoy it and keep newly planted stock watered. Established plants need no water and no feed at this point, and feeding now produces exactly the soft leafy growth that stops flowering.
As the flush thins and the middle of the plant starts to look bare, shear the whole thing back by a third, cutting above a pair of good leaves. Regrowth appears in two to three weeks and carries a second flush into late summer. Cutting half the clump a fortnight before the other half spreads the display rather than concentrating it, which is usually the better result in a small garden.
The tender shrubby kinds need no cutback at all. They simply keep flowering, and the only intervention is shortening the odd stem that has grown out of proportion to the rest. Deadhead spent spikes on both groups by cutting back to the first good leaf pair rather than snapping off the dead tip.
Autumn: take the cuttings, then stop tidying
Early autumn is the one date in the salvia year that cannot be moved. Take cuttings from every tender shrubby salvia you would be sorry to lose, while the plant is still in growth and before the first frost. They root in two to three weeks and overwinter in almost no space. This is the difference between a bad winter being an inconvenience and a bad winter being a loss.
At the same time, stop deadheading the hardy kinds and let the last spikes stand. From here on the correct action in the border is to leave things alone. The dead top growth insulates the crown, holds snow and shelters overwintering insects, and clearing it away in autumn is the commonest reason a hardy salvia does not reappear.
Move containers of tender salvias under an eave or into a frost-free space before the weather turns wet, and pull any mulch back from the crowns of plants in the ground so that water drains away from the base rather than being held against it. If your soil is heavy, this small job matters more than any frost protection you could apply.
Record the date you took the autumn cuttings and how many rooted, alongside the date of your first frost. Over two or three seasons that tells you exactly how early you need to take them in your own garden.
Winter: leave it alone and keep the stored plants cool
There is no work to do on hardy salvias in the ground through winter. The stems stay standing, the crown stays covered, and the temptation to tidy is the main risk. If you must clear the border, clear everything except the salvias.
Overwintered tender plants and rooted cuttings need cool rather than warm conditions, around 45F to 50F (7C to 10C), good light and only enough water to stop the compost drying out completely. Warmth produces long soft growth that attracts whitefly and red spider mite and gives you a weak plant in spring. Check the undersides of the leaves once a fortnight and remove any yellowing foliage that falls into the pot.
Use the quiet weeks to look back at the season's notes. Which positions flowered well, which mildewed, which plants flopped, when the second flush actually opened after the cut. Those answers are the ones that improve next year, and none of them can be reconstructed from memory once the border is bare.