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Salvia uliginosa UK is the outlier in the salvia world — almost everything about growing salvias emphasises free-draining soil, but uliginosa actually tolerates, and in some conditions prefers, consistently moist ground. This makes salvia uliginosa UK genuinely valuable for the significant number of UK gardeners with heavy, moisture-retentive clay soils where most salvias would struggle and fail.
Beyond its unusual soil tolerance, salvia uliginosa UK is remarkable for its airy sky-blue flowers on tall stems reaching 120–150cm, flowering from August through to November — one of the latest-flowering salvias available. The loose, open flower clusters are outstanding for pollinators in September and October when very little else is still in flower. It spreads by underground stolons, so plant it where it has room to expand or be prepared to manage it annually in spring.
TL;DR — Quick Summary
Quick Facts
| Common name | Bog sage |
| Hardiness | RHS H2–H3 — tender; take cuttings in August |
| Soil | Tolerates moist, even clay soils — unique in the salvia world |
| Position | Full sun to partial shade |
| Flowering season | August to November — exceptionally late |
| Height | 120–150cm in good conditions |
| Habit | Spreading by stolons — forms expanding clumps |
| Pollinators | Outstanding late-season value for bees and butterflies |
Salvia uliginosa is the outlier in the salvia world — almost everything else about growing salvias emphasises free-draining soil, but uliginosa actually tolerates, and in some conditions prefers, consistently moist ground. The name gives it away: uliginosa means “of bogs” in Latin. This makes it genuinely valuable for the significant number of UK gardeners with heavy, moisture-retentive clay soils where most salvias would rot.
Beyond its soil tolerance, uliginosa is remarkable for its airy, late-season blue flowers on tall stems that work beautifully with grasses — and for its exceptional pollinator value in September and October when very little else is still in flower.
Unlike most salvias, uliginosa spreads by underground stolons to form an expanding clump rather than a neat mounded bush. This spreading habit is worth knowing about before you plant — in the right conditions it can spread quite vigorously and may need managing in a smaller border. In a large naturalistic planting or combined with robust grasses it’s an asset rather than a problem.
The flowers themselves are distinctly different from other salvias — small, sky-blue, produced in loose open whorls on tall wiry stems rather than the dense upright spikes of nemorosa or the shrubby bushy habit of microphylla. This airy, see-through quality makes it one of the most effective late-season plants for naturalistic planting design. It reaches 120–150cm in good growing conditions.
☀ Position
Full sun to partial shade — more shade-tolerant than most salvias due to its native riverside and bog habitat. A south or west-facing position is ideal but it will perform adequately in a few hours of daily shade, particularly if the soil is consistently moist.
💧 Soil & Water
The key difference from other salvias: uliginosa tolerates consistently moist soil and doesn’t require the sharp drainage that most salvias need. It will also grow in free-draining soil if watered regularly. Avoid waterlogged, stagnant conditions — moist but moving is ideal.
🌿 Pollinators
Outstanding late-season value — the loose open flowers attract a wide range of pollinators including both long and short-tongued bumblebees, as well as hoverflies and butterflies. Peak flowering in September and October when very little else is available. See our pollinators guide.
❄ Hardiness
RHS H2–H3 — tender in most UK gardens. Take semi-ripe cuttings in August for reliable overwintering, or in mild southern gardens try a generous mulch in October. The spreading stolons sometimes survive even when top growth is lost. See our overwintering guide.
📅 Flowering Season
August to November — one of the latest-flowering salvias available. In mild autumns it continues well into November, providing colour and pollinator forage long after most other plants have finished.
✂ Pruning
Cut back in spring once new growth appears from the base. Leave old stems through winter for crown protection. In established clumps, thin the spreading stolons in spring if the plant is spreading beyond its intended area. Deadheading is not necessary — the airy open habit looks good even as flowers fade.
Molinia caerulea ‘Transparent’
The most natural companion — both are tall, airy and see-through. Molinia turns gold in autumn at exactly the time uliginosa peaks. The two together create one of the best late-season combinations available.
Miscanthus sinensis varieties
Tall, architectural grasses that echo the height of uliginosa without competing. The silver plumes and sky-blue flowers work beautifully together in September and October.
Persicaria amplexicaulis
Shares uliginosa’s tolerance of moist conditions and flowers simultaneously in late summer and autumn. Deep red or white flower spikes create a strong colour contrast.
Vernonia crinita
Tall ironweed with deep purple thistle-like heads — both plants share the same moist-tolerant, late-season niche and work together in a naturalistic late-summer border.
Salvia uliginosa UK is available from Middleton Nurseries — grown at our Staffordshire nursery using peat-free compost and dispatched nationwide alongside our full range of tender and hardy salvias.
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