Plants that make ideal living mulches

We make a point of not mulching our annual garden beds over winter as we want the sun to be able to hit the beds directly – warming them up as much as possible. Plus, mulching in winter creates the perfect habitat for slugs that’ll ravish your plants. However, come summer time we’ll happily mulch our annual crops to prevent evaporation, slow down any weeds and provide organic matter for our soil food web. But in our perennial gardens (herbs, orchard and perennial vegies) it’s generally a different story. Having the soil covered permanently (or close to it) prevents evaporation, fosters a stable soil food web and will generally improve the health of all plants. So rather than only relying on buying mulch, we also grow living mulches that have multiple benefits – they reduce evaporation, can provide nutrients to the soil, attract bees, fix nitrogen and help stabilise steep slopes. Here are a few examples: Vetch (vicia sativa) is a nitrogen-fixing ground cover that (to our delight) actually volunteered in our garden. We foster it in our herb garden where it fills in any gaps between plants and adds a little purple when it flowers. Comfrey: We’re big fans of comfrey (symphytum) and plant it among our orchards and globe artichoke patch where it also helps stabilise the slope. Its deep tap root can “mine” minerals into its leaves which we then chop and drop beneath our fruit trees where they release these minerals. Clover: We use white clover (trifolium repens) throughout our small edible forest garden. This quick growing, nitrogen-fixing ground cover is super hardy and popular among the honey bees. They’ll flock to the flowers, which of course ensure the fruit trees nearby benefit from pollination. But don’t plant this in your annual vegie patch as it’ll become invasive and you’ll never get rid of it! Mixed floral: Easy on the eye and a hot spot for the bees, a mixed-floral living mulch system is a great way to go for both the soil and often your tummy. A lot of these flowers are edible, including the nasturtium and calendula flowers – add these to your salads to add a little rainbow to your dishes. We use nasturtium (tropaeolum), sweet alyssum (lobularia maritima) and calendula (calendula officinalis) as our main living mulch options as they self seed prolifically, are tough and the bees love them. We’re big fans of plants that can handle the ‘tough love’ approach to gardening. You won’t find anything that needs constant pampering on our property – we’re all about minimal input and maximum output. Native plants: We currently have the creeping boobialla (myoporum parvifolium) beneath our young grevilleas and tea trees and creeping saltbush (rhagodia spinescens) under our olives. The boobialla grows incredibly close to the ground, while this particular variety of salt bush will grow to around 30cm before spreading out – they’re both beautiful and vigorous plants. Obviously there are many more plant options available to you depending on your climate and context. The key thing to aim for is to choose plants that benefit, rather than compete with one another. As a general rule, most ground cover plants will have shallow root systems, meaning they’ll be suitable as a living mulch around fruit trees or larger plants that generally have a deeper root system. At the end of the day, maintaining bare soil in your perennial crops is a lot of work (think weeding and watering). Why bother when you can grow a living mulch. The benefits are many, and while it still requires input from you, it’s significantly less and the rewards and more!