Twin Cities Tree Talk

Are you tired of watering trees constantly? It's incredible just how much water is recommended for a thirsty tree every day during drought. A large 40" diameter tree would benefit from 40 gallons of slow trickle irrigation on a dry hot day! Installing a mulch ring is one of the best ways to dramatically increase soil moisture moderation and consequently tree drought resistance.

Homeowners commonly overestimate the power of fertilizer. Fertilizers like miracle-gro cause explosive growth in tomatoes and scots allows turfgrass to thrive. Surprisingly, trees in compacted city soils often suffer when high nitrogen synthetic fertilizers are applied; burns to roots can occur while enhanced growth rates for stressed plants increases vulnerability to a myriad of ailments. Trees in the urban environment are weakened from a lack of organic material seen in the forest setting. Decades of leaves, sticks, and logs decomposing into the soil creates that soft porous medium rich in biological activity we associate with a healthy forest environment. Urban environments do not receive this decompaction and become even more compressed with construction and foot traffic. Mulch material helps keep air pockets present for a healthy rooting environment. Mulch has additional benefits with greater biological activity and a slow release of nutrients.

The most important step to install a mulch ring is to space material from the tree trunk. At least 4 inches of spacing prevents trunk rot diseases and deadly girdling root formation. HOA developments frequently have huge piles of mulch against trunks....trees slowly die 5-30 years later as girdling roots wrap around the trunk similar to tight belts on a waistline. The tree actually kills itself with trunk vascular tissue choked off from these girdling roots.

The mulch ring can cover as large an area as aesthetically reasonable. A larger area is usually desirable as tree roots sprawl 2-3 times the diameter of the canopy. Thickness for maximum benefit only needs to be 2-4 inches.

Do not put landscape fabric or plastic weed barrier down under the mulch. This fabric can girdle the tree and will dramatically reduce air exchange; tree roots can suffocate.

Choose a mulch from trees like Oak or Ash. Do research on other wood mulch types....Black Walnut material such as mulch contains a natural herbicide juglone that harms many tree species.

Ask local tree trimming outfits if they can deliver mulch for you. They would rather make a quick stop at a nearby property than deliver to a commercial chip dump location. Coordinate what type of mulch you want and where you need it. This mulch may have leaves/sticks so keep that in mind. For natural areas, this method can be free and efficient for a large volume of material.