Every year I get several calls from my customers asking “what’s that slimy stuff on my growing in my bark? It looks like a dog threw up in my shrub bed!” That “slimy stuff” has a very apt name. It is called slime mold. It may look vicious, but it is harmless. The following text was taken from the Sylva Corporation. The photo of the slime mold was taken in my yard.

With the rains and heat of summer come the vast array of slime molds (also known as dog vomit fungi) appearing in mulch. They appear in several sizes and colors with no definite shape.The mold may change on a daily basis from a bright yellow netting to a tan powder to a dark brown dried blob.
Slime molds get their nutrients from dead organic matter, including mulch.Although slime molds may grow on plants, they do not harm them.Slime molds will eventually disappear on their own. If you want to speed this process, rake the mulch to prevent air drying. For additional information regarding these molds, try the following websites: http://www.waynesworld.palomar.edu/slime1.htm
http://www.coopext.colostate.edu//TRA/PLANTS/slime.html
http://www.herbarium.usu.edu/fungi/FunFacts/SlimeMold.htm

A while back I wrote an entry (Peg’s Pond) about building a pond for my sister-in-law Peg. . A planting season has gone by, and as you can see by the pictures, the place has changed quite a bit! Peg now has some Koi and a few goldfish, and they have taken a real liking to their new home. Peg has really done something right, because they have started breeding, and she saw her first batch of Koi hatchlings last Spring, with more hatching throughout the summer. The pond plants have done well, and combined with the fish, she has achieved a good biological balance to keep her pond healthy, and created a nice aquatic ecosystem.
Click photos to enlarge

Part of the design process of determining the location of the pond was preserving the great view from inside the house. There is a wetland area behind her home, and we wanted to incorporate the pond with the view. Now with plants maturing, they help make a smooth transition from the house to the pond to the wetlands. We used mostly perennials and grasses, many of which were native to the area. The photo at the left shows the main waterfall feeding one of the two streams we constructed. That’s Joe Pye plant and Back-eyed Susan around the waterfall.
Even though the picture doesn’t show it, the stream in the photo is one of two streams. It exits in to a small upper pond, which in turn cascades into the main pond. Peg told me she even saw some baby Koi in the upper pond!

The view from her picture window has now become a real focal point in her home. Peg does a lot of work out of her home for people that have mind-body coordination issues (she uses a process called Brain Gym therapy), and the view of the pond and waterfall provides a very relaxing atmosphere for her clients.
The two streams have been a real nice touch. They have created more interest, and the sound of the two streams adds a lot of dimension to the sound of the water. The photo to the left shows the other, larger stream headed down to the main pond.

Peg has really done a great job on her pond. I’m looking forward to watching it grow and mature.”Hey Peg… I could use some Koi for my pond, and I see that you have a few to spare…..”

Right: Peg and I checking out some new baby Koi.

Those doggone walnuts. They are one of our most valuable hardwood tree species, but they can be a real nuisance in the home landscape. Each year, several people will ask me why they can’t seem to get anything to grow under their walnut tree. Just the other day I was at a customer’s house looking at some problem plants and sure enough, they were trying to grow right under a walnut tree.

Walnuts release a chemical into the soil called juglone. Juglone is present in all parts of the tree, but can be especially high in the roots and walnut hulls. The highest concentration in the soil is directly beneath the canopy of the tree, but it can be present in lesser concentrations anywhere the roots are present (which can be out as far as the tree is tall). The presence of juglone can also be affected by soil type, with sandy well drained soils tending to have less of it present.
Juglone can be toxic and even fatal to some plants, while others don’t seen to be affected by it. Affected plants show signs of wilting, yellow leaves, stunted growth, and eventually death.

So what’s the solution?

1) Susceptible plants can be planted in above ground containers or raised beds. If you build a raised bed, make sure you line it with plastic so the roots won’t grow up in to the soil or you’ll have the same problem all over again. Make sure you rake up any leaves or hulls that end up in the bed.
2) Cutting down the walnut tree can be a good long term solution, but the decaying roots will still release juglone into the soil, and it could be several years before the juglone is out of the soil.
3) Plant susceptible plants as far from the drip line as you can. The farther the better.
4) The most obvious solution is to install plants that are more resistant to juglone. The thing is, there hasn’t been any proven method of determining which plants are truly resistant. Any research I found on plant tolerance was based on simple observation. I compiled the following list of tolerant/intolerant plants using my own observations and checking out the university extension sites of Cornell, Purdue, Michigan State, University of Minnesota, Ohio State, and the Morton Arboretum. I have only included woody landscape plants. For a complete list including annuals, perennials and vegetables, click on the hyperlink to each of the sites listed above.
Just because a plant is listed as susceptible or non-susceptible does not guarantee that it will grow under a walnut tree.Therefore, I listed plants as “more tolerant” or “less tolerant”. I found a few plants that were listed as tolerant on one list and non-tolerant on another list. The list is compiled of plants that the sources had in common.

Trees
Less tolerant: White Birch, Hackberry, Linden, Pine (in general) Black Alder, Magnolia, Norway Spruce, Crabapple, Apple, Silver Maple, Arborvitae.
More tolerant: Catalpa, Eastern Red Cedar, Hemlock, Elm, Locust, Red Maple, Sugar Maple, Redbud, Poplar, White oak, Red oak, Serviceberry, Hawthorn, Beech, Sycamore,

Shrubs
Less tolerant: Azalea, Rhododendron, Black and Red chokeberry, Hydrangea, Lilac, Mugo pine, Potentilla, Cotoneaster, Yew.
More tolerant: Some Viburnums, Juniper. St Johnswort, Euonymus, Forsythia, Honeysuckle, Ninebark.