Documents: Container & Small Space Gardening:

Squirrels, Crabgrass and Walnut Trees

How to prevent squirrel damage; use a crabgrass control soon; and what to grow near a walnut tree!
by Art Drysdale
by Art Drysdale


Art Drysdale, a life-long resident of Toronto and a horticulturist well known all across Canada, is now a resident of Parksville, British Columbia on Vancouver Island, just north of Nanaimo. He has reno-vated an old home and has a new garden there. His radio gardening vignettes are heard in south-western Ontario over radio station Easy 101 FM out of Tillsonburg at 2 PM weekdays.

Art also has his own website at

March 9, 2003

adBlackWalnut.jpg (62937 bytes)
The black walnut (Juglans nigra) is a beautiful, majestic tree, perhaps not as a street tree as seen here, but nevertheless, a gorgeous tree. However, if you have one, you’ll have to be very careful about what you plant anywhere near it. Author photo.

Many gardeners have distaste for raccoons, but generally are more forgiving when it comes to squirrels. Well, that’s often the case until it comes to the point of the squirrels either digging up newly planted tulips, daffodils and crocus in the autumn, or the flower buds of various bulbs are bitten off in the spring--not too long from now--again by those otherwise “cute” squirrels.

What to do!

When planting bulbs in the autumn, it’s often easy to cut sections of nylon netting and place it over the bulb area, just below the soil surface. This generally will deter squirrels from digging up the bulbs. In the spring, nylon netting can be cut into smaller pieces, and placed curled or even folded, in between the bulbs. Again, the squirrels do not like to get their feet caught in this material, and usually will avoid the area in future.

There are many, many other suggestions for the prevention of squirrel damage. As with raccoons, many gardeners say garlic powder, or a mixture of it with cayenne pepper will keep them at bay. In the case of each of these “home remedies,” it seems to me that for everyone who reports success, I can cite someone who has tried it with no success.

There is another possible solution to the problem. For several years now, some old friends at Yule-Hyde Associates (specializing in bird feeders, and other equipment for birds) have offered a US product called Squirrel Away. Virginia Yule is my contact, and you can check out their site at It is intended to be mixed with birdseed to make the seed unattractive to squirrels, and so they leave the seed for the birds. Most gardeners have had experience with so-called “squirrel-proof bird feeders” that have turned out to be nothing more than a great challenge for adventurous squirrels. Squirrel Away is the answer to this problem.

The product is a natural one, but that doesn’t mean it can be used without due consideration for safety.

Squirrel Away is actually a finely ground (powdered) form of the plant Capsicum which is actually similar to the strongest Jalapeno pepper, but about 25 times as strong. Now that’s hot! And, squirrels don’t like it!

After a couple of nibbles, they’ll go to another source of food, leaving your bird feeder solely for the birds. The powder is either mixed with the feed, or if it’s a course feed like sunflower seeds, spread over the top of the birdseed when it is first put out. Generally, squirrels will not come back to a feeder that has been treated this way. It may be necessary to re-apply the powder after a rain.

You will likely be interested to know what the birds think of this hot stuff! In fact, they cannot notice it, and it is actually a natural source of vitamins (particularly vitamin A), proteins and lipids for all birds. They love it!

I mentioned safety, and it’s important to keep in mind that you should be careful not to mix this product with bird seed under windy conditions when the wind might carry the fine powder into your or another person’s face. You should avoid touching the powder, and if some does get on the skin, a simple rinse with water will wash away any potential burning.

That brings me to other possible, related uses of Squirrel Away in the garden. Though it is not so recommended by the manufacturers and distributors, Squirrel Away may be the answer to some gardeners’ problems with squirrels attacking parts of plants. For example, applied to young tulip foliage being bitten off by squirrels, it should deter them. However, keep in mind you wouldn’t want to do this if there was the possibility of children or pets touching the dusted foliage.

Still another possibility worth trying, is the application of Blood Meal--an organic fertilizer. Keep in mind that when wetted, blood meal has a strong, undesirable smell. And, when buying this product do not allow the seller to talk you into a “similar product--Blood & Bone Meal.” The latter will definitely not be nearly as useful in keeping away rodents as the straight blood meal. As with the Squirrel Away, blood meal will have to be re-applied after every rain or watering from a hose.

All in all, my preferred anti-squirrel treatment is nylon or plastic garden netting which is now sold in a wide variety of colours (black is generally least noticeable at ground level). But, Squirrel Away is definitely a possibility under certain conditions as described.

Few weeds make a lawn look as ugly as does crabgrass. Even dandelions and plantains at least stay green and blend in with the green grass blades, although their seed heads do look bad for a few weeks.

Crabgrass, on the other hand, once its wide blades turn purple in mid summer, gives the entire lawn an off colour. Yes, much worse than lawns that have gone dormant as a result of a lack of rain or lawn watering restrictions. Many people fail to take advantage of the easy solution because the crabgrass preventative must be applied early in the spring, before crabgrass seeds germinate.

What these chemicals do, essentially, is put a thin coating over the soil surface that stops crabgrass seed and grass seed from germinating. Since crabgrass seed only begins to germinate when the soils warm up substantially, you have up until the time when the lilacs are in bloom to apply it. To be safe and sure, however, it's best to have it on two weeks before the lilacs come into flower!

Visit any good garden centre and they'll be pleased to rent or loan you the right type of spreading equipment, and thus no crabgrass! Two other important points: you should not sow grass seed just before or after applying crab-grass preventer, and you should NOT rake the lawn harshly after the application.

Almost all lawn fertilizer manufacturers offer a combination fertilizer/crabgrass preventer product, and this is by far the best way to apply the only real good solution to crabgrass. Basically there are two chemicals used for crabgrass prevention--Dacthal is the older solution and is now virtually phased out. Dimension is the newer one. The latter has a slight advantage in that it not only stops crabgrass germination, but also actually kills any tiny young seedlings that may have already germinated. That means that if you are applying when the lilacs have actually come into bloom and there may be a chance that some crabgrass seed has already germinated, a product containing Dimension is more likely to give you complete control.

Do remember that all these products must be watered in to be effective.

Every year for the last nine I’ve been at the Success With Gardening show (March 13 – 16 this year at the Toronto International Centre, just north of Pearson International Airport) and one question always comes up--in fact it is often the most asked. It has to do with gardens with black walnut trees in them or near them.

This is an age-old problem dating back to the year 37 (yes 0037!) A.D. However, only in 1928 was the compound, juglone isolated in many plants in the walnut and hickory families, and found to be the cause of the death of other plants coming in contact with the roots of black walnut, as well as butternut and hickory trees.

Although the poisonous compound is found in the roots, leaves, bark and husks of the nuts of the black walnut, toxicity is usually only noted when the walnut’s roots come in direct contact with susceptible plants.

Most people ask just what plants are susceptible. Actually, quite a long list including tomatoes, blueberry, apple, pear, blackberry, azaleas, rhododendrons, cinquefoil, red and white pine, and other evergreens are all likely to show symptoms, and eventually die.

As to plants that are not bothered, there is also a good list from which you may choose. First, the most obvious is bluegrass--it thrives! Many vegetables other than tomatoes are OK; for example, snap beans, lima beans, sweet corn, onions, and parsnips generally grow fine. Some years ago, there was a report of beets with a strong flavour that may have been related to black walnut roots.

Some plants seem to be on the borderline of susceptibility; i.e. sometimes they are affected, and other times not. The explanation would appear to be the amount of soil moisture. Plants such as sweet peppers, lilacs and Viburnum (snowball, for example) may be affected in constantly damp soils, and not in open, dryer soils.

If it’s flowers you’re trying to grow, stay away from peonies. But, you should have no difficulty with anemone, cyclamen, Hosta, Iris, Lilium, forget-me-not, daffodils and narcissus, primroses, salvia, and, the most popular of all annuals (one that will grow well in the dense shade provided by a black walnut) all impatiens.

Incidentally, just removing a large black walnut will not guarantee freedom from the effects of the juglone compound in the soil. That could take at least another year, although killing the tree’s stump with an herbicide will give freedom from the compound sooner.

And do remember, that it’s not just black walnut trees that contain juglone in their roots. A question just recently had to do with a problem near a butternut tree. The gentleman said he was having trouble with rhododendrons. I told him I was sure that the problem was juglone.

Happy gardening under the walnut tree!

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