As hydrangeas begin to fade with the arrival of autumn, gardeners can still carry out one vital task now to ensure a stunning display next year. October typically brings mild enough conditions for small outdoor jobs, but within the coming weeks, the first frost will begin to bite in certain parts of the country.
This can place considerable strain on hydrangea roots, which sit close to the surface and are particularly vulnerable to harsh weather. If hydrangea roots are repeatedly subjected to the cold, they can sustain damage, leaving the plant struggling to produce flowers come spring, or even beginning to die back entirely.
Using Fallen Leaves as Free Mulch
Jessica Walliser from Savvy Gardening has revealed a straightforward way to protect hydrangeas without spending a penny — simply gather up the fallen leaves already lying around the garden. She said: "Fall mulching of hydrangeas leads to well-insulated roots that can better survive weather extremes and the ups and downs of freeze-thaw cycles."
She added: "Do not over-apply mulch (two to three inches is plenty), and do not pile it up against the plant's base or trunk. Make a doughnut shape of mulch around your hydrangea. You can also use shredded fall leaves for this job."
Why Mulching Matters in Autumn
Mulching is a gardening technique that involves laying a layer of material around a plant to create a natural protective barrier, shielding it from the worst of the elements. Gardeners apply mulch as temperatures drop to shield the soil from repeated cycles of freezing and thawing, which can cause considerable cold damage by saturating the ground with icy water.
Autumn is an ideal time to mulch hydrangeas, not only because temperatures will begin to fall, but also because there will be an abundance of fallen leaves available, which can be used to create a substance known as leaf mould. Leaf mould insulates the roots, helping to prevent temperature fluctuations and stopping the ground from repeatedly freezing. It also enriches the soil with nutrients while remaining a gentle material, keeping the roots in good health throughout winter and ensuring a stunning display of blooms come spring.
How to Make and Apply Leaf Mould
Leaf mould is a natural and cost-free way to support hydrangeas, though the one downside is that it can take considerable time to produce, so it's worth planning ahead and allowing sufficient time for the leaves to decompose. It can be made at home, or leaf mould mulch is widely available at most garden centres for those who prefer to use it straight away.
To make it yourself, gather fallen autumn leaves and place them into a large plastic garden bag. Pierce holes in the sides and base of the bag to allow for drainage. A compost bin can also be used if preferred, though leaves take longer to break down than standard compost, so keeping a separate bin for leaf mould is advisable. It can be beneficial to shred the leaves using a mower before placing them in a container.
After that, simply leave the bag or bin somewhere in the garden, ideally in a spot that is both damp and warm, as this will also help to accelerate the process. Once the leaf mulch is ready, spread it in a circle around the hydrangeas, approximately two to three inches deep into the soil around the root area.
Mulch retains a considerable amount of moisture, so avoid piling it up or allowing it to come into contact with the hydrangea stems, as this can saturate the ground and lead to rot. Simply spread it a few centimetres away in a doughnut shape, topping it up periodically when the mulch begins to look sparse. This mulch should provide sufficient protection for a hydrangea once the colder weather sets in, meaning the plant need not become stressed or suffer damage over the winter months.
