Under planting a large 15m leylandi

janeseeber · August 2021

We've bought a house with a mature garden including a large south facing leylandi. We removed the lowest branches and the soil under it gets full sun all afternoon. But the ground is covered in the shedding leaves of the tree so grass doesn't grow.. I thought of creating a patio but it will always need sweeping /cleaning! Could I make a (raised) bed here and what should I plant in it please? Will the shed leaves kill the plants? Thanks for any advice!

Fairygirl · August 2021

Hi @janeseeber - It won't be easy whatever you do.

I wouldn't put a patio in, but it would depend on the size you're thinking of doing. You may have plenty of room without all the bits falling on you.
A raised bed is certainly a reasonable idea, but bear in mind that the hedge will soak up all the moisture, and raised beds always tend to be drier [freer draining] so you'd need to plant accordingly, and you'd definitely need to add as much organic matter as possible.
Any stuff shed onto the plants won't necessarily cause the plants a problem as such, but they can clog plants up if they're smaller, so again - the choices would be important

janeseeber · August 2021

Thanks for the advice, I guess vegetables won't be a good choice. It is just one large tree and not a hedge, does that make things any different?

Fairygirl · August 2021

it might, but without seeing a photo, it's hard to judge

JennyJ · August 2021

Underneath conifers is one of the most difficult places in a garden for planting. I think the roots of the tree would find their way into a raised bed and suck out all the moisture and goodness. Large containers (even up to a size that looks like a raised bed but with a base) might work better but will need a lot of watering, so give some though to how you'll manage that. You'd probably want a hose permanently nearby.

steephill · August 2021

How much of the garden does the tree occupy? Is it there for a purpose (privacy) and do you love it? Don't feel obliged to keep it just because it was there when you bought the house. It will double in size when fully mature, they are impressive specimen trees but you do need to have enough space for them to shine in that role.

bédé · August 2021

In my front garden I have a Cedar deodara. Cedars always have raised. dry , dead soil below them. I grow a ring of ivy that also hides a drain cover. I have to clean the deodara stem once a year.

I chose Hedera "Curlylocks", it comes by other names. I think that a variegated ivy might light up a dark place better, but would it grow so well in the shade? Outside the ivy ring I have ca 2 feet of less often cut grass. I never water.

bédé · August 2021

By the way. Inbetween the houses I grow a Lleylandii hedge. 3m, closely trimmed 2x a year. For 40 years it was as good as yew. In shade and poor builders' soil, it is now beginning to lose lower branches and get rather thin.

I have planted between each lleylanddi plant small plugs of yew with the idea of their eventually replacing the conifers, and with minimum disturbance of the existing roots. One failure in year one. 25% failure in 3 years. The plugs don't seem to have rootesd outside the plugs. I water frequently. The idea is not yet a complete failure.

Topbird · August 2021

I definitely wouldn't put in a raised bed that was open to the soil below.

I did that near a walnut tree. Grew veg absolutely fine for 2 - 3 seasons then things started to struggle. When I eventually dug down into the (18" high) raised bed it was nearly completely full of fibrous walnut tree root. No wonder the tree had put on a tremendous growth spurt - I'd done a fine job of watering and feeding it😝

You might get away with raised beds if you laid concrete slabs with proper hardcore underneath and then put deep raised beds on top of that - say 2 or 3 chunky sleepers deep. If you use pressure treated sleepers I don't think you'll have too much of an issue with drainage. To an extent water will drain from the gaps between and under the sleepers plus you could put a layer of drainage stones in the bottom. I've always found it harder to keep raised beds sufficiently watered - I've yet to have one that has become even remotely water logged.

Metal frames and netting could probably be used to protect the veg from tree debris. Use the right nets and it will also protect from pigeons, cabbage whites, etc

Fairygirl · August 2021

15 metres of leylandii is a big drain on everything.

I don't think raised neds would be great either, but it would depend on the site and how near they were. You'd need to put a sturdy root barrier in, or the completely solid barrier suggested, and then have weep holes for drainage instead. Pretty much all conifers are shallow rooted.

They definitely dry out readily @Topbird, even here, especially once they're planted up. It would be very difficult to keep anything well enough watered.
I have various things under the conifers I have here, but only stuff that can cope with the odd spell of drier weather too, although we do get a lot of rain, and it does get through the canopy.

We'd need to see the site though.

seacrows · August 2021

A really tough ivy might manage. Raised beds with roofs? The shed leaves of a lot of conifers have the purpose in the wild of suppressing all growth near the trunk of the tree, so your tree is working well.
I'd probably think laterally and put something ornamental, sculptural and brightly coloured there. Fairy lights for night time maybe.

Under planting a large 15m leylandi

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