Should You Rake Leaves Off of Perennial Garden Beds?

Leaves are the perfect addition to the garden in autumn. They add beautiful red, orange, and yellow colors to the landscape. They have dozens of beneficial uses for the soil, bugs, and plants. Learn how to use them, and you’ll never see leafy covers the same way! They’ll go from a hassle you have to deal with to a gift from the natural world.

There are some stipulations for perennials and fall leaves. You’ll want to uncover the plants’ crowns when they sprout in spring, and you’ll want to let evergreen species access light. Aside from these two concerns, there’s no reason not to let them stay where they fall!

The Long Answer

Whether or not you should rake depends on your garden setup, your neighborhood’s regulations, and how many leaves you receive in autumn. The decision is up to you! Try leaving them in one section and raking them away in another. Then, compare the results in spring to see which you prefer.

Leaves Insulate Soil

The biggest protection leaves offer your perennials is warmth and insulation. They form a thick barrier that traps heat below ground and blocks incoming freezes. Frost-tender perennials stay safe below the leaf blankets and are more likely to survive until spring. 

If you remove this upper mulch layer, then you’ll let frost penetrate the soil. Temperatures will drop, and perennials will be more susceptible to cold damage. Plus, it’s extra work to move them! Save your back, and let nature’s resources do their thing without interruption.

Not only does fall leaf cover insulate the soil, but it also prevents weeds from sprouting. They’ll stay stuck underneath the thick cover, and seeds that fall on top can’t access the soil below. Keep your perennials warm and banish weeds by letting the leaf cover insulate your garden soil.

Bugs Need Leafy Cover

Not only do you help perennial roots thrive when you leave fallen foliage, but you also help the bugs and critters that hide underneath them! Many animals like bees, fireflies, and beetles, rely on leafy cover to hide from predators and stay warm. When you leave leaves, you allow them to overwinter without disturbance.

The more beneficial insects in your garden, the healthier your ecosystem will be! Predatory insects eat pests that harm our crops, like aphids. Other bugs, like beetles and their larvae, provide food for birds and hungry mammals. By helping one species, you help them all!

If you must rake the leaves away, do so gently to avoid harming sensitive critters. Make a leaf mold or compost pile with leaves to provide additional habitat space. I make a compost pile every autumn and am surprised to find resting bees and ladybugs inside it when spring arrives. 

Organic Matter Boosts Soils

My favorite reason to leave the leaves is to boost soil fertility. A thick leaf cover decays throughout fall, winter, and spring, forming a thick mat of rich and crumbly humus. Humus is the natural end product of decomposition; it’s a small black particle full of organic matter. Soils are healthy when they’re rich in humus.

Adding biodegradable foliage can be a valuable aid for sites with too much clay, sand, or silt. Organic matter decomposes into soil particles. These particles help break up clay or silt and increase absorption rates in sandy sites. Incorporate leaves wherever the soil is poor, and let them work their magic throughout winter.

Leaves are rich in carbon and have some nitrogen in them, as well as other trace minerals. They’re best for amending soils where woody plants grow because wood consists mainly of carbon. When you add a leafy cover or leaf mold to their roots, you assist them in growing thick, strong, resilient trunks and branches.

Leaf Mulch Promotes Fungi

Not only do leaves help plants and animals, but they also promote beneficial fungi! Mycorrhizal fungi need leafy covers so they can spread their root-like mycelia deep underground. Mycorrhizae is a special fungus that connects tree roots to the resources they need in exchange for sugar. The fungi gift minerals and nutrients in exchange for their sweet reward. 

When you leave the fallen resides, you allow these underground mycelia to spread wider as they connect more trees and plants, and form a resilient family. If you rake them away, there’s a chance you may disturb or disrupt these pathways. It takes years for intricate networks to form, but it only takes a few seconds to break them up.

Avoid disrupting beneficial fungi and let them thrive without disturbance. You may not see them, but you’ll know they’re working their magic below the soil during the cool months. After years of this care, you may see fruiting mushroom bodies near tree roots in autumn and spring! The mushroom heads are signs that there’s a healthy underground fungal network. 

Keep Evergreens Leaf-Free

The only plants that don’t benefit from leaves on them are evergreens. If you have low-growing evergreen ground covers or dwarf conifers in your beds, you’ll want to keep their stems leaf-free. As they grow low to the ground, fall leaves can fall on top of their green foliage and smother their sprouts.

Once every week or two in autumn, it’s a good idea to take a garden walk. You’ll see leaf-covered evergreens and can help free them before they start suffering. To clean them, simply shake or dust off the fallen foliage. Let them sit on the soil and cover the roots so they provide insulation benefits without harming the canopy. 

Some particularly tough plants to clean are sprawling cotoneasters, kinnikinnik, and euonymus ground covers. You may use a leaf blower to push the leaves off the stems. Or, try this clever trick! Place micromesh netting over the plants, and let the leafy cover fall onto the netting. When there’s a thick layer, pull the netting off to free your specimens. 

Uncover Sprouting Perennials

As spring warmth arrives and days lengthen, herbaceous perennials erupt out of the ground. Some species can penetrate leaf cover, like daffodils and tulips. Others require aid to sprout without issues. It’s especially important to clear the plants’ crowns in areas with thick winter snow cover. Leaves may not decompose fully, and they’ll create an impenetrable layer for the sprouting stems.

How do you know where your perennials are underneath the leaves? Use this trick in autumn to mark their locations. Use a stick or wooden stake, and stab it into the ground near the base of the plant. Leave it throughout fall and winter so it remains a marker in spring. Remove the leaves around it, and watch as your plants sprout anew!

Another easy option is to leave last year’s stems in place. This works well for upright perennial species with woody or erect stems. Think of plants like camas, daylilies, and coneflowers. They leave seed heads, woody flower stems, and dead foliage. Instead of removing them in autumn, leave them as markers for spring.