Get matched with top mulch and topsoil pros in Doon, IA

If you hire a professional landscaper, you could expect to pay between $90 and $660 to install three cubic yards of river rock. (That’s based on the average river rock installation cost of $30 to $220 per cubic yard.) However, the exact price depends on the kind of river rock you choose. Crushed limestone and riprap are some of the more affordable options, while boulders and Arizona river rock are pricier.

Mulch is made from natural materials, which will break down and add nutrients to your soil for better plant and soil health, so removing old mulch is unnecessary before putting down new mulch. However, if you live in a particularly moist area, it’s possible that the old mulch will harbor fungus or mold, which can hurt plant health. If you notice these issues, you might want to consider removing the old mulch first. Otherwise, save time and money by placing new mulch right over the old mulch.

The best size rock for your landscaping depends on the design, as different boulders serve different purposes. If you want to group boulders to create a natural-looking cluster, you’ll need a range of sizes. Otherwise, here are some suggestions:

• Small boulders (smaller than 12 inches across): Best for landscape edging and fire pits 

• Medium boulders (12–24 inches): Best for retaining walls and water features

• Large boulders (more than 24 inches): Best as standalone landscaping features, steps, or walkways.

Of course, you can mix and match sizes to create a unique display.

A light layer of mulch can help protect a tree, retain moisture, and keep the soil healthy. However, it’s important to avoid over-mulching or piling the mulch up around the trunk of a tree, a practice notoriously called “volcano mulching.” That piled mulch can increase the chances of rot and disease on the tree trunk as well as overwhelming the soil, which needs access to a certain amount of air. Topped trees have it hard enough: mulch sparingly while they heal.