Garden tips for August | August 6, 2010 | Palo Alto Weekly | Palo Alto Online |

Palo Alto Weekly

Real Estate - August 6, 2010

Garden tips for August

Check out the root system for basic plant health

by Jack McKinnon

Pull out a plant once in a while. All good gardeners do, and here is why: Half of a plant is out of sight. It is under the ground. The best way to know what is going on with the half of a plant you cannot see is to pull it out and look at it.

Of course, if you want to put it back then it is a good idea to dig it out carefully, brush or wash off the soil and then you can replant it. The important thing to know is that unless you look at the roots you are often only half sure how healthy the plant is.

This month's tips will be on what to look for when you finally get up the courage to pull up a plant.

1. Identify (Latin name as well as common name) your plant. If you don't know what you have, call me at 650-455-0687 with a description or bring a sample to a nursery and get it identified. Then look it up. The easiest way is on the Internet. Do a search using the Latin name and sift through the sites to find the most informative one on your plant.

2. Choose a specimen that is looking unhealthy and dig it out or pull it out if it looks like a goner anyway. This way learning may not cost you your best plants and — who knows? — maybe you can save this one by identifying the problem and solving it.

3. Check the moisture of the whole root system. Feel the roots and the soil that surrounds them to note if there are dry areas or soggy ones. A good even moisture level appropriate for the plant you are looking at is required. Obviously water plants need wet roots and cacti need dry roots; everything in between needs various degrees of the two extremes.

4. Look for healthy white or evenly colored growth. If the color varies around the root system there could be a disease or fungus affecting it. Healthy roots are abundant, fresh looking and even in color.

5. Smell the roots. Be careful with Euphorbia because the sap can burn you. If they smell like a swamp, they are suffering from root rot, a fungus that causes roots to disintegrate. If they smell like good healthy soil or slightly rooty they are probably OK.

6. Look for bumps, boils, knobs, hollow sections or growths on the sides or tips of the roots. Only a few plants such as beans, peanuts and potatoes have anything but smooth or relatively even root branching. If it looks sickly it probably is. Again you can bring a sample to a nursery and ask for identification of the problem or call me and I will give it my best shot.

7. Check for obvious chewing. I know this sounds obvious but gophers are everywhere and don't always pull a plant down into their hole. Imagine having a whole tree in your living room. They often just eat as they go, leaving the rootless plant to wilt and die.

8. Look at the crown of the roots. This is where the root meets the trunk or stem of the plant. This area should be an even transition without any rot or growths on it. If the trunk or stem of the plant is moist it may have been planted too deep and replanting it higher may just solve the problem, if it is not too late. Often I see plants declining because they have been planted too deep.

9. If the root system checks out and is healthy looking, then there may be a soil nutrition or fertilizing problem. This calls for another column. Replant your plant if it looks like it may stand a chance. Water it and watch it for a couple of weeks. If it doesn't come back, it may be time to amend the soil and change your fertilizing program.

10. When shopping for new plants, it is good practice to look at the roots before you buy them. Everything from six-packs to 15-gallon pots can have root-bound plants in them. Root-bound means the roots have hit the side of the container and started going round and round. Don't buy root-bound plants. You're only asking for trouble.

Buy plants that look healthy on the top and under the soil and your chances for successful gardening will go up significantly.

Good Gardening.

Garden coach Jack McKinnon can be reached at 650-879-3261 or 650-455-0687 (cell), by e-mail at Visit his website at


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