Is Mulch the Answer to All Your Garden Problems?
Mulching is touted to be the panacea for every challenge and need in our garden forests.
But after disappointing results in our mediterranean forest, we turned to… living mulch.
The Benefits of Mulching
Ok… I’ll just get it over with…
Everyone praises mulching in preventing weeds, providing habitats for useful insects and microorganisms, moderating soil temperatures, decreasing soil erosion, increasing water infiltration and soil moisture, increasing biological activity within the soil and with the right type of mulch – even feeding the soil as it decomposes and increasing nitrogen content…
I get the principle, and I totally agree with it.
But… And it’s a big “but”…
In my specific situation:
our mediterranean food forest is on a mountain side (1,200m/4,000ft) facing south;
during most of the year the sun is scorching;
we only have 2-3 rain events – when we have some soft rain for a week at a time (usually October/November, January/February and or April/May).
The Drawbacks of Mulching
It seems that any organic mulch (chop and drop leaves and twigs, straw, hay, compost, wood chips, sawdust, pine needles… those are the ones I tried) simply dry out and oxidize…
Since water is scarce, and very expensive, we only use water to directly water the fruit trees (twice a month) and vegetables (once a week)… We can’t afford to keep the mulch moist.
It takes years for even the tiniest, most fragile leaves to decompose and I suspect that more nitrogen is used for the decomposition process than what is eventually being made available for the plants.
And worse – these types of mulch often prohibit the little soft rain we get to actually reach the soil.
We Needed Another Solution
After years of observing our mulch doing nothing much, I chose to change strategy and focus on perennial living green mulch.
We started with drought tolerant herbs, mainly thyme, sage, and oregano, as well as lotus berthelotii – a beautiful, endemic, perennial creeper… but moved almost entirely to an unexpected perennial ground cover…
Succulents as the Best Living Mulch Option
- Succulents are hardy and drought tolerant;
- They flower most of the year;
- They grow fast and cover large areas pretty quickly;
- They keep the soil temperature well below the temperature of adjacent uncovered soil;
- They don’t compete with the trees for water and nutrients – because of their shallow root systems, preference for lean soil and low demand for water.
Succulent as Living Mulch Experiment
I couldn’t find anything online about successfully using succulents as living mulch, but it just made sense to me – so I chose to experiment.
I took a few cuts from different succulents and without ceremony, growth hormone, or soil amendment – I simply planted them in little, shallow holes all over the property – keeping them 1m/3ft from the trunk of any fruit tree.
I did that after the first rain, knowing that for the next few days it will rain some more.
And that’s it…
15 Months Later
Here are some pictures to demonstrate the results after just 15 months…
More than Just Beautiful
Bear in mind that each of these succulents started its life as a tiny cut – not bigger than my finger, and got no irrigation whatsoever, even during the harsh summer last year (many days of up to 40C/104F) and no rain for 7 months.
When I lift the crawling brunches, I see quite some life in the dark soil.
When I touch the soil underneath it’s definitely cooler than the soil nearby, and after any precipitation it stays moist for weeks or longer, while the adjacent bare soil dries up within hours.
The succulents cover is so dense that no weeds pop up between them…
These succulents are flowering most of the year and they’re always surrounded with our honeybees and other pollinating insects… In fact they’re some of our top performing bee plants.
Unfortunately…
Succulents do not provide nitrogen to the soil…
… not through their roots, nor through massive dead leaves.
So to amend it, we first mulch the area with compost and nitrogen fixing twigs and leaves (mainly from our tagasaste and acacia trees – see our mediterranean nitrogen fixing trees), make holes in the mulch and plant the succulent cuts into the soil.
This way the succulents grows over the mulch, and by keeping the soil moist and cool for longer period – it helps the soil microorganisms break down the nitrogen loaded mulch underneath.
Am I Crazy here?
I know it’s an unconventional living mulch, and I wish I could find some more research-based conclusions that are less anecdotal than mine.
But… when I compare the areas in my forest garden that has been covered with succulents to the areas I used traditional mulching – the difference is stark in favor of the succulents.
I will continue expand my succulent distribution and varieties, and experiment with more ways to make sure the soil is always protected.
I’d love to learn from you…
I would love to hear your opinions, experiences and questions concerning using succulents as living mulch… And what other living mulch would you recommend…