disease, lawn care, native plants, plant care, plant selection, Uncategorized

Trees Need Extra Love in a Drought

We just bought a new house and it was empty for some time.  I use my irrigation system a couple of times a week, but should I water my mature trees more than that this summer? (pecans, oaks)  We haven’t had much rain for the last 6 months.   Anthony S.

Most of the nation seems to be in feast (flood) or famine (drought) mode, doesn’t it?  While hard on people, too little or too much water is devastating for plants that cannot escape their environment.

If you have a rain gauge – which I STRONGLY RECOMMEND – you’ll know exactly how much natural rainfall has occurred and whether or not supplemental water is warranted.  Depending on the tree’s age/size and variety,  you might need to apply more water several times during the growing season to keep it healthy.  If the drought continues, consider a regular schedule for watering your trees.  Texas A&M University offers insight into tree care through their EARTHKIND® website, giving a number of tools to both prevent and curtail damage to your landscape due to lack of rain.  Here are some of their suggestions, along with some of my own.

  1. Look to your trees to tell you they are thirsty.  Premature foliage yellowing and/or leaf loss over the whole tree, leaf margin (outside edge) burns and curling, and eventually loss of canopy beginning with the inner, lower branches.  How do you save a dead tree?  You don’t, so watch for early cries for help.
    Drought-stressed elm tree (from Austin American Statesman)
  2. Remove grass and weeds under trees –  which compete for available water – and replace with mulch.
  3. Do NOT use fertilizer on drought stressed plants.  Encouraging new growth is the last thing they need.  And NEVER use weed ‘n’ feed products near trees.  (I suggest there is no reason to use these products at all!)
  4. Know what kind of trees you have and then treat them according to their needs.  (The Smithsonian released a NEW APP for that – LEAFSNAP. Don’t depend on it, though.  It is still a work in progress….) Just as with people, each variety of tree has specific requirements.  Your mature pecan will require a significant amount of water, but certain oak trees (like bur oak) need less than others (like water oaks).
    HIT: 10 gallons of water per inch of trunk diameter for each watering. Measure trunk diameter at knee height. General formula: Tree Diameter x 5 minutes = Total Watering Time. from City of Boulder, CO
  5. A soaker hose set out under the ENTIRE canopy of the your mature trees is the most efficient way to water deeply.  Watering only at the trunk not only doesn’t help, it could HURT your tree, encouraging a fungal infection where the water sits.  (I’d add you might want to see exactly how much water is coming out of the hose. Put a tuna can under a section …..how long does it take to get an inch of water standing in the can?  For you engineer types, here is a WEBSITE that helps you convert the inches to gallons, the most common measurement.)
    6.  If you are planting a new tree in your landscape, GO NATIVE!  You will save precious resources – including water and YOUR TIME – if you install a variety that already will feel at home at yours.
    Whether a plethora of patio plants in pots, an oversized orchard or a standard suburban site, know what plants you have and what their preferences are in order to help them THRIVE in any weather.  Plants are integral to OUR health, but they depend on YOU to keep them healthy!

    MYTH: SOAK YOUR TREE’S TRUNK – against the trunk only, a soaker hose can cause more harm than good!


5 thoughts on “Trees Need Extra Love in a Drought”

  1. Leslie, that’s the PITTS, isn’t it? I mean literally. Pitts are notorious for their susceptibility to fungal disease. That is especially true of older ones in lots of shade. And they get a double whammy when there’s no sun to dry them off and no breeze to dry them out in a well protected area like where yours are.

    University of Florida has a pretty comprehensive paper as a FREE downloadable PDF (http://plantpath.ifas.ufl.edu/takextpub/FactSheets/pp0029.pdf) on variegated pittosporum problems. Look at the photos and see if you can find one that resembles what you are experiencing with your plants. If not, let’s talk again, okay?

    As far as what you are seeing on the ground, sounds like a harmless mold……harmless to the plant, anyway. (Mold allergies are a different post for a different writer.) Compost is always a great top dressing, but if you have a nice layer of mulch down (which is probably the host of your mold) and in a forested area where leaves can compost on their own, sounds like you’re already doing everything necessary to keep the roots covered and fed.

    Keep me informed on your investigation. c:

  2. I think this might be drought/heat stress related … I have variegated pittosporums tobiras in my front yard – along the front of my house. No sun. Shade all day. Yesterday I noticed one on the end looks like it is dying – shriveled leaves – light green/very pale color. At first I thought it looked thirsty – but the area gets irrigated regularly and I’ve checked the soil – damp. Around the trunk at the soil line is a grayish-whiteish looking mound – at first I thought it looked like ice cream salt poured out – but a closer inspection reveals it is a damp clay-like texture. I thought about removing the gray stuff and putting on some Nature’s Way compost (not more than 2″ deep, though). Could this be a type of fungus? Is there any hope? What do you think about the compost idea?

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