What to do with all the leaves!?!
– zum deutschen Text – Two weeks ago I wrote about the spectacular autumn colour. By now some trees have dropped most of their leaves, whilst others are only just starting to think about it. The beech hedges at the Garden Academy are only just starting to turn their beautiful coppery colour.
The large chestnut tree that stands at the bottom of our small garden and the oak which grows just across the boundary with our neighbour’s garden have by now shed most of their leaves. In some areas I remove them, in others I do not touch them. In some places I add more.
Sweep leaves from steps and terraces
In autumn they can quickly become a hazard. Under packs of soggy leaves the surface never dries at this time of year. The areas can quickly become slippery as moss and algae grow. Particularly on wooden surfaces, the timber will deteriorate quickly.
Rake leaves from Paths
Although I love walking through a thick carpet of crispy leaves, I have been raking the path regularly. At this time of year the garden rapidly turns into a state of disorder as the visually strong forms of ferns and perennials collapse. It is therefore important that the designed structure of the garden, which in summer is lost in the jungle of vegetation, becomes visible again. In the long-term, a layer of organic matter from composting leaves would also build up on top of our hogging paths. This in turn would encourage moss and weeds to grow.
Clear lawns by mowing the leaves
Although I encourage leaves in the beds and borders, the lawn is the only vegetation area which has to be raked. If leaves are left, the grass will be deprived of light and air and fungal diseases can build up. Raking it will slightly scarify it, but the quickest way of collecting the leaves of the lawn is with the lawnmower. This has two advantages: the lawn gets its final cut of the season and the leaves are chopped and mixed with grass. As grass is a good activator it will speed up the decomposition of the chopped up leaves, making them ideal mulch for beds, or at the foot of hedges.
Remove leaves from water
At the moment the oakleaves float on top of the water of our water feature, so that it is barely recognisable. I occasionally fish them out with a rake. Our birds’ bathing paradise may be easy to keep clean, but in larger ponds it become more complicated to remove the build-up of old leaves that will sink to the bottom and become foetid.
Free the tops of evergreen shrubs
A low cloud-trimmed hedge of Ilex crenata separates our garden from the neighbours’. On these, as well as on the low hedges that partly enclose the border, oakleaves accumulate in amongst the rigid twigs. Like on the grass, these little nests of leaves prevent light and air from getting to the plant, increasing the risk of disease build-up. With a rake they can be raked out, or just pluck them off by hand.
So what do I do with my leaves?
Where possible, I like to leave them where they fall as they are an important part of the natural recycling system. Nature relies on this organic matter as soil improver and for the nutrients it contains. Although trees reabsorb some of the nutrients from the leaves before they drop in autumn, some such as calcium stay in the leaf. Once the composting process is completed, the plants will be able to re-absorb these vital nutrients. Covering the soil also stops it from drying out.
Horse chestnut leaves are removed
These are the only ones I do remove out of the garden. They harbour the larvae of the Horse Chestnut Leafminer. It is important to take these leaves away before the start of spring, as then the adults of this destructive pest will emerge. These leaves go off to the local authority composting collection, as their composting facility is large enough to produce the necessary heat that kills off harmful pathogens.
Walnut leaves can stay
If you have a walnut tree in your garden, collect the leaves and let them compost for at least 6 months. Alternatively, use them as a natural herbicide and apply them as mulch to weedy areas.
Mulching shrub areas
The other leaves are used to mulch the beds. A thick pack is raked onto the base of the bamboos, where they will provide moisture and nutrients to keep them happy within their rootbarrier. But also the woodland-loving Japanese maple and hydrangeas will benefit greatly from a good layer of leaf litter. It will keep the soil cool and moist during the hotter summer periods.
Leaves in borders
Also amongst ferns and perennials I like to leave them. It protects the plants, and encourages blackbirds to rummage around, in search of insects and potential pests. These thin layers of leaves can be covered by a layer of compost to keep them in place. The whole will compost much more quickly than when you pile them high into one heap. Mixing green matter such as grass clippings will also accelerate the process.
Thick packs also have been put at the base of our three palm trees (Trachycarpus fortunei) and evergreen magnolias (Magnolia grandiflora). These are not perfectly hardy, but cope with some frost. So far they have done well in our very sheltered inner-city courtyard garden, and I just like to give them a little extra protection. Should they suffer severe frost damage, it is important to make sure the rootsystem is unharmed, so that a plant can sprout again from the base. A cosy layer of leaves at the base of plants standing in pots on the terrace will provide protection and stop the plants from drying out.
The list of areas where leaves should be removed may seem long, but as three-quarters of our garden is planted, it means the raking and sweeping is quickly done and the results are hugely rewarding. Re-defining the structure is so valuable at this time of year!