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MMWD Blog: Think Blue Marin

Welcome to our blog! Written by staff at MMWD, “Think Blue Marin” explores all things water in south and central Marin—water supplies, conservation, new projects, watershed management, and more.

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Aug 14

Plant Stress

Posted on August 14, 2015 at 9:44 AM by Ann Vallee

by Charlene Burgi

We are all doing a great job conserving water during this prolonged drought. But despite our vigilant care and attention to our gardens, plants are experiencing dry conditions—especially the native trees and shrubs on the outskirts of our properties. This is the place where irrigated gardens meet up with wildlands or open space.

Drought conditions will show up in plants in various ways. Sometimes the plant will just look off-color. Of course wilting is a sure indicator. Plants will also become stunted as roots fail to grow, and soon-to-follow the fruit and flowers stop bearing. A dismal state, to say the least!

Plants under severe water stress become susceptible to invading insects and disease. It is almost as if those deadly pathogens and insects seek out frail plants! For example, a healthy pine tree can "pitch out" assailing beetles. On the other hand, beetles flock to trees under duress, which typically cannot fend off the attack.

Rocky Fire
 The Rocky Fire as seen from our cabin
A call from my son told of the vast number grey pine trees (Pinus sabiniana) dying and dead along the road as he traveled to our cabin in the mountains of Lake County. His observation came as no surprise. I am certain the frass (insect debris looking like sawdust) of boring beetles would be quite apparent if he'd had the chance to inspect the trees up close. It is little wonder that Lake County is under siege with two terrible wildland fires spurred by prolonged drought.

Dying, drought-stricken plants are a significant fuel source as we witness the devastation of our wildland fires this year. While we cannot control the wildland vegetation, we can be very diligent about our gardens that interface with these lands.

First, assess the vertical growth in your garden and how it relates to the horizontally growing plants. In other words, most often fires get into the crowns of trees from brush or vegetation growing underneath the trees. Typically a grass fire cannot get into the crown of a tree unless the lower limbs of the tree are within range of the grasses. And, typically, grassland fires move through more quickly than if the flames are lingering on a woody plant. With that said, limb up your trees at least 10 feet. Keep shrubs away from the base of trees and choose groundcovers that are more succulent or have thick leather-like leaves, such as Trachelospermum (star jasmine) in a shady area or perhaps Mahonia repens for sun exposure. Keep vegetation sparse in those areas that interface with open space, and before planting check for plants that are less flammable than those containing a lot of oils. Prune all dead wood out of plants including perennials and groundcover. Do not plant ornamental grasses near outlying fence perimeters as they can act as a torch if ignited.

Keep hydrating your own vegetation following MMWD's outdoor water-use guidelines. Reusing your water—for example, via a laundry-to-landscape graywater system—is another good way to help plants get adequate water during this drought. You are doing a great job. Now for all of us to safely get through the fire season.

Mystery Plant ID'ed

Mystery plant
 Mystery plant identified as Phacelia campanularia
In my last blog (before losing internet connection), I wrote about being stumped by the identity of a wildflower growing in the garden. It was a sure bet that casting the inquiry out to you, the reader, I would find the answer. I patiently waited for the internet issue to resolve itself, and three days later the answer presented itself thanks to Marie Narlock! She conferred with her friend, Faith Brown, who correctly identified the mystery plant as Phacelia campanularia (desert Canterbury bells).

A special thanks to all of you who took the time to help out. This little beauty just finished its bloom cycle and hopefully will present itself again next year!

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