If your patio turns green and slippery, it’s usually algae and grime building up in damp, shaded conditions — not a mystery stain.
RHS explains that algae/lichen/moss commonly colonise hard surfaces and many mosses favour damp, shady conditions, often appearing at edges and in cracks.
RHS also notes algae doesn’t necessarily damage the surface but can make it slippery.
What the green usually is
Green film = algae
Algae thrives where water lingers and sunlight is limited.
Tufts/cushions = moss
RHS describes common moss forms on paths and patios and notes many favour damp, shady conditions.
Black/white spotting = lichen
Lichen is stubborn and often needs repeated cleaning + prevention steps.
Why it gets worse in weather
Patios go green faster when:
- Shade slows drying (north-facing areas, fences, trees)
- Leaves trap moisture (creating a damp layer on the surface)
- Poor drainage leaves puddles (water sits = algae party)
- Cool, wet spells mean surfaces never fully dry
RHS points to damp/shade as key enabling conditions for these growths.
Why it becomes slippery
RHS explicitly highlights that algae can make surfaces slippery, which is a safety issue, not just an appearance issue.
That’s why quick cleaning before winter is often a smart move for households with kids/elderly visitors.
How to stop patios going green so quickly
1) Sweep regularly
RHS recommends regular brushing to prevent growths taking hold.
2) Clear leaves and organic debris
Leaves hold moisture against the surface and slow drying.
3) Clean cracks/joints
Use a pointed tool to remove moss in paving cracks.
4) Fix standing water areas
If one section always stays wet, look at drainage/runoff routes — prevention works better than repeated cleaning.
5) Consider timing
A clean during a mild, drier window gives the surface time to dry and helps the result last longer.
1) https://www.chilterngardenmaintenance.com/blog/planting/best-time-to-plant-shrubs/
Meta title
Best Time to Plant Shrubs in the Autumn vs Spring) + Pro Tips
Meta description
When is the best time to plant shrubs in the? A practical guide by type, container vs bare-root, plus planting tips for better survival.
Best time to plant shrubs in the
If you want shrubs to establish quickly with fewer failures, timing matters. You can plant many shrubs year-round, but the best results usually come when the soil is workable and watering needs are lower.
The RHS guidance is straightforward:
Container-grown shrubs can be planted at any time, but they settle best between autumn and early spring.
Deciduous shrubs: best from autumn to early spring, as long as soil isn’t extremely wet or frozen.
Evergreens: best planted in autumn or spring.
Container-grown trees/shrubs are easier in autumn/winter because they generally need less watering than spring/summer plantings.
The simple answer: autumn usually wins
Autumn planting is often best in the because:
soil is still warm enough for roots to grow
rainfall helps establishment
summer heat stress is gone
This aligns with RHS advice that shrubs settle best between autumn and early spring.
Best time to plant by shrub type
Deciduous shrubs
Best: autumn → early spring
Avoid: extremely wet or frozen ground
Evergreen shrubs
Best: autumn or spring
Container-grown shrubs
Can plant: any time
But best establishment: autumn → early spring
Spring vs autumn: which should you choose?
Choose autumn if…
you’re planting a lot
you want fewer watering demands
the site is sunny/exposed and dries quickly in summer
Choose spring if…
your soil is heavy and tends to waterlog in winter
you missed autumn
you’re planting evergreens and want them rooting before next winter
Planting success checklist
RHS emphasises establishment care, especially watering in dry spells after planting.
- Right planting depth (don’t bury the stem)
- Firm in properly (no air gaps)
- Mulch (keeps moisture in, reduces weeds)
- Water during dry spells for the first couple of years