Friday, December 26, 2014

Garden Doctor: Japanese maples are worth the extra work

From page A7 | November 14, 2012 |

Question: I see Japanese maples growing around town. Some seem fine and others seem to be suffering. What’s the secret? Is the Davis water’s boron at fault again?

Answer: The Garden Doctor has a keen fondness for Japanese maples. These small shrubs or trees rarely get taller than 25 to 30 feet; many are much smaller, have beautiful shapes, sizes, colors of foliage, twigs and bark. They are multi-stemmed, and prefer a north or east exposure, possibly sheltered away from drying north winds. A few days of hot, north wind or prolonged days of 100-degree heat take a heavy toll on these delicate beauties.

A thick layer of mulch around the roots helps to maintain maximum hydration. Only a few thrive in the hot afternoon; summer sun and salt build-up (boron) can be an issue.

The boron issue can be somewhat remedied by flooding occasionally to leach out salts. Burned edges on the leaves are sure signs of salt build-up and from the Doctor’s experience often occur in small pots. Dissectum type maples (lace leaf maples with deeply divided and dissected leaves) are more susceptible to boron burn than broader-leafed specimens.

The Doctor has a source of non-boron water and has been successful in growing healthy maples in pots using this water. The beauty of these Japanese maples is so appealing the Garden Doctor cheerfully accepts the additional labor involved. The new “Sunset Western Garden Book” has an excellent section on Japanese maples with detailed descriptions of many varieties.

Q: I have found two peculiar things in my yard. One is brown and seems to have attached itself to the side of a pot and the other is on my lawn, yellowish, looking like something regurgitated. Is either anything I need to be concerned about as far as destroying my garden?

A: What you have described is slime mold. The yellowish substance is referred to as dog vomit slime mold for obvious reasons. Slime molds are interesting substances. They are not true molds or fungi, but rather very primitive, single-cell organisms. They pose no threat to humans or plants.

People often refer to them as mold or fungi because they grow in the same type of environment — warm, wet conditions where there is decaying material and bacteria to feed upon. On lawns, the gooey substance may suffocate the grass. You can rake the slime mold or blast it with a stream of water. Mowing also will remove it. On its own, it disappears within about a week after it has dried and becomes a dusty substance.

There are more than 900 species of slime mold worldwide and they are found in a wide variety of colors from off-white to orange to brown to brick red. In urban areas, one is most likely to find them in mulched areas. Most of the time they spread out as on lawns, but when there is no room to spread or food supply is sparse, these single-cell organisms will congregate. Check out the IPM website for pictures at

Speaking of “peculiar”: the Garden Doctor was surprised when digging out an old rose bush to find, just below the soil surface, a hard object attached to the base of the bush.

It was nearly the size of a grapefruit, and varied in color from off white to brown. A quick search on Google identified the mystery as “crown gall disease,” caused by the bacterium Agrobacterium tumefaciens. The source for this information was a Cooperative Extension publication from Oklahoma State University on rose diseases that included a photograph of a gall very like the one dug up in Davis. The advice from OSU would be well taken for any rose transplanting situation:

1. Transplant only disease-free plants;

2. Avoid wounding during transplanting;

3. Remove infected plants as soon as galls are observed, along with all soil in and adjacent to the root system;

4. Take care to avoid injuring roots or crown area when transplanting roses; and

5. Disinfect pruning and cutting tools frequently with a 10 percent dilution of household bleach.

In the case of the old rose, it was destined for the trash. Master Gardeners, including the Garden Doctor, have confidence in advice from Cooperative Extension sources, both in California and in other states, because they are research-based and subject to peer review.

— Send questions, addressed to the “Garden Doctor,” by email to, voice mail to 530-666-8737 or regular mail to UCCE Master Gardeners, 70 Cottonwood St., Woodland, CA 95695. Be sure to include your contact information, because any questions not answered in the Garden Doctor column will be answered with a phone call or email to you.

You can request the Yolo Gardener newsletter delivered by email and learn more about the Master Gardener program in Yolo County at



Special to The Enterprise

  • Recent Posts

  • Enter your email address to subscribe to this newspaper and receive notifications of new articles by email.

  • .


    Transit survey: 47 percent ride bikes to UCD campus

    By Special to The Enterprise | From Page: A1 | Gallery

    Exchange students bring the world to Davis

    By Anne Ternus-Bellamy | From Page: A1 | Gallery

    Pastor has many plans for CA House

    By Jeff Hudson | From Page: A1 | Gallery

    Playing Santa

    By Enterprise staff | From Page: A2 | Gallery

    Goats help recycle Christmas trees

    By The Associated Press | From Page: A2 | Gallery

    Special holiday gifts

    By Sue Cockrell | From Page: A3

    Woodland-Davis commute bus service expands

    By Enterprise staff | From Page: A3

    Learn fruit tree tips at free class

    By Enterprise staff | From Page: A3

    Davis Bike Club hears about British cycling tour

    By Enterprise staff | From Page: A3

    Pick up a Davis map at Chamber office

    By Enterprise staff | From Page: A3

    Sierra Club calendars on sale Saturday

    By Enterprise staff | From Page: A3

    Explorit: Get a rise out of science

    By Lisa Justice | From Page: A4

    NAMI meeting offers family support

    By Special to The Enterprise | From Page: A6

    Yoga, chanting intro offered

    By Enterprise staff | From Page: A8



    Blamed for her sister’s rage

    By Creators Syndicate | From Page: B5

    How much for the calling birds?

    By Creators Syndicate | From Page: B5

    Steve Sack cartoon

    By Debbie Davis | From Page: A10

    Many ensured a successful parade

    By Letters to the Editor | From Page: A10

    Thanks for putting food on the table

    By Letters to the Editor | From Page: A10



    Two more for the road for 9-1 Aggie men

    By Bruce Gallaudet | From Page: B1 | Gallery

    Patterson is college football’s top coach

    By The Associated Press | From Page: B1 | Gallery

    Clippers get a win over Golden State

    By The Associated Press | From Page: B1 | Gallery

    NBA roundup: Heat beat Cavs in LeBron’s return to Miami

    By The Associated Press | From Page: B10 | Gallery





    ‘Unbroken': A bit underwhelming

    By Derrick Bang | From Page: A11 | Gallery

    Folk musicians will jam on Jan. 2

    By Enterprise staff | From Page: A11



    Passat: Roomy, affordable sedan with German engineering

    By Ann M. Job | From Page: B3 | Gallery



    James J. Dunning Jr.

    By Special to The Enterprise | From Page: A4

    Floyd W. Fenocchio

    By Special to The Enterprise | From Page: A4



    Comics: Friday, December 26, 2014 (set 2)

    By Creator | From Page: B7

    Comics: Thursday, December 26, 2014 (set 1)

    By Creator | From Page: A9