REDWOOD: PUT IT ON THE GROUND, NOT IN IT

Redwood - apart from being a most magnificent tree in its natural state - has attributes both positive and negative when considered for a landscaping material.

Redwoods are one of a group of trees called conifers, which generally exhibit superior characteristics in insect and decay resistance; an absolute advantage as a long-lasting landscape mulch or ground cover. 

Redwood’s natural resistance comes from its high levels of tannic acid and phenol. The pleasant odors produced that we associate both with the tree as well as with chopped or shredded redwood are evidence of this characteristic. Dependant upon where in the tree the material is harvested, redwood can contain 10% – 30% phenol (the main and toxic acid). Redwood material that is younger and dry or “top growth” is less toxic. Redwood material that is bark or that is older and higher in moisture level is more toxic. When you purchase redwood you end up with either or a combination of both.

These natural attributes which are so beneficial in preventative maintenance measures on ground surfaces, are less than user-friendly in the soil or a growing medium. When present, plant growth will depend upon the sensitivity level of the particular plant, but inherent toxicity will inhibit the growth of micro organisms and germination, and is poisonous to living organisms such as fungi and bacteria that promote plant growth.

Redwood’s characteristics are shared with a few other conifers such as cypress, pine, eucalyptus, and cedar to mention a few. Eucalyptus leaves actually drip mildly acidic phenolic, and that is why there is very rarely anything growing under a eucalyptus tree. That is also why we do not include eucalyptus in our compost core material. Cedar - also to be avoided in soil amendments - contains three toxins; phenol, creosote, and thujaplicin (known for its potent anti-fungal and ant-bacterial properties); reasons we do not include cedar in our compost core material!! Cedar is extremely effective as an insect repellant in the closet!

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