mulching on a slope

our property is basically a big long ditch - a section of a small spring-fed stream and the slopes on either side of it. there’s not a lot of flattish ground, so many of my growies are getting planted on slopes. one of my big challenges is trying to get the mulch i use around them to stay put. i have a few strategies, including staking logs of junk wood across the slope to create a mini-swale to catch what i can, and covering woodier mulch materials with a layer of dead leaves (or chop and drop green stuff, depending on the season) and then sometimes using dead branches with lots of twigs to keep the leaves from blowing around. but the slopes are steep, and the rain are sometimes pretty heavy, and i always lose some amount of mulch down the hill, frequently mixed into taller plants where reclamation is difficult.

what other techniques are working for you, mulching on slopes? what else might be worth trying?

Hi Greg, I have a couple ideas, but a question first.  Does the water flow evenly down across all parts of the slope or are there sections with heavier and sections with lighter water flow?

Eric

i suppose it’s irregular enough that it must be variable to some degree. in general when picking spots to plant trees etc, i’ve been favoring the more level spots (read: less steep, not actually level). i don’t think they’re necessarily more high-flow areas.

Greg,
Although most of our land is just gently sloping, I have a little escarpement towards the top of my tree field which is pretty steep, probably 1 in 1.  I only plant woodland trees in this bit and have generally left them to their own devices.  As you've also found, extreme gardening is a little tricky.  I did have some little junipers, which I wanted to tuck in a bit more carefully and what I did I have since regretted.  We had some lovely carpet underlay made mostly from jute shoddy, like a thick felt, which I couldn't resist using.  Cut with a slit in for the trees to poke through jit was quite effective and pretty long lasting.

The problem with the underlay was the bit that wasn't jute....through the felt there was a mesh of thermoplastic, probably polythene, I'd hoped that I'd be able to fish this out of a beautifully cleared spot as the underlay degraded, but this wasn't to be.

The grasses grew over and through the felt so that the plastic net was hopelessly entangled.  I tried mulching over the top with cardboard hut had limited success so I've had hell's delight getting it back out again.  However the material apart from that was excellent.
Most of the sheet materials I think of that would work would be rather expensive at any scale (natural woven carpet and matting, really thick papier mache made from biomaterials). The best suggestion I have is to use bigger twiggy materials that will support each other and living mulches that will build up in situ like bracken and comfrey.

Watching....

Greg,

Growing up we had a patch of ground that constantly washed out and made a gully 4-6’ deep.  Eventually the problem was solved partially by planting tall zebra grasses in the direct path of the glow of water.

Maybe in your case you don’t need 6’ tall grasses.  Maybe just some 6” tall grass spread along a long distance might break up and slow water rolling over the surface.

My 2 cents,

Eric

We have daylilies and irises planted to break up the water flow and hold down the soil on our steep mulched slope.

Greg,

The other way we solved the gully problem was at the back end of the gully.  Eventually we filled in the gully with a lot of fill dirt, but at the back end we piled in a bunch of broken concrete, riprap.

I don’t think riprap is appropriate in your situation, but maybe you could make lanes running parallel to the ridge, perpendicular to the slope with grasses/lilies on the high side and some medium rocks on the low side to hold things back.  The idea would be to slow water down with vegetation and hold things back with rocks.

If possible, and depending on your time, energy and budget, I might be tempted to leave a little walking space and then repeat with another lane/bed just downhill.

These are just ideas.  Maybe you could get by with no rocks and two rows of grasses/vegetation if the slope was gently.  I actually like the idea of lilies as I think bulbs plant, establish and spread quickly and easily.  These little bands of vegetation might also be a good place to put in pollinators.  Cone flowers might be good as they spread by both seed and rhizomes, flower prolifically and attract bees.

Greg, if you like this idea you can probably adopt any one of numerous variations depending on your own personal tastes and circumstances.  These are just my thoughts and you certainly know best based on your own experience on your own land.  I am curious what solution you eventually come up with.

Good Luck!!

Eric