Helping Your Trees During Extended Drought

What can we do to buffer our trees against these prolonged and extreme drought conditions? Watering is perhaps the obvious answer, but watering is often not practical or possible for various reasons. Even if you water often, your tree could still greatly benefit from mulch beds over roots. 

Establishing a strong mulch bed that covers the root zone of your trees has myriad benefits.

The mulch insulates the soil, keeping it cool and moist during these hot and dry days.

Mulch can protect against soil compaction and prevent water runoff. Soil compaction is one of the main detractors from urban tree health. 

As the mulch decomposes it will add a wonderful rich compost to the soil, helping to nurture your trees and mimicking the natural nutrient cycling that occurs in forests.

Mulch can provide a home for beneficial insects and microbes that will add to a thriving biome for your tree to grow in.

Eliminating competition with turf is another great benefit of mulch.  Turf roots are in direct competition with tree roots and they typically win the fight for available water, forming a thick root mat that can cover the tree roots. 

Ultimately mulch can save you money on watering and arborist intervention for ailing trees.

This amazing compost was formed after less than 2 years in this mulch bed that we made.

There are many types of mulch available in the Boulder area.  Some are better for trees than others, some should be avoided.

First off, avoid the ‘gorilla hair’ type of mulch.  Not only is it expensive, it is also ineffective and often detrimental to soil health.  It can form a mat that is difficult for rainwater to penetrate.  It is also nearly inert with little to no active decomposition.  In general, avoid any mulch that is heavily processed and or dyed.

The best mulch that you can readily get in the Boulder area is the mulch that is sold at Western Disposal on the East side of Boulder.  Not only is it great for the soil, it is also the most affordable mulch around.  There is also a free mulch pile available at the City of Boulder forestry yard. 

Chipper truck mulch is usually pretty good stuff however it can be inconsistent and sometimes the loads can be full of undesirable chips.

Landscape supply centers in the area have many decorative mulch options that you may prefer, however supply can be inconsistent so you may end up waiting some time to get the mulch you want.  Of the more decorative mulches, I suggest the bark mulch, small, medium or large.  Not only is it beautiful and fragrant, it also has good shape and size to help improve soil health.  Just be sure to supplement with a thin layer of compost if you choose bark mulch. 

Generally you want to look for mulch with large chunks of wood that is slightly decomposed. A mix of chunky, woody pieces and compost is preferable.

One final note about mulch beds and soil health, avoid the use of landscape fabric!  Landscape fabric and/or weed barrier can severely damage soil health, limiting water penetration and smothering soils, causing them to become anaerobic.  A healthy soil needs free exchange between below and above ground.

Planting companion plants in the root zone will not only help to build the biome and soil profile but will also help to keep weeds out of your mulch bed.  Until a healthy soil is established it may be necessary to periodically hand weed in order to remove unwanted plants. 

One final caution about mulch beds, be sure to not pile to mulch directly against the tree. This can cause unwanted issues to arise. Make sure that your trees root flare is visible and no mulch is piled against the trunk.

If you want help designing and installing a mulch bed please reach out to us and we will let you know what we can do to help your trees.