Growing Concerns 562: Fertilizer, cocoa hulls and dogs

Early Spring!

Learn the rules of fertilizing, the gardener's game of numbers


Dear Janet,

I have a large perennial bed with 25 roses, columbine, daisies, coneflower, lilies, etc. You mentioned in a previous column to fertilize our beds with a 10-10-10 fertilizer. I was unable to find that ratio but purchased a 13-13-13, hoping that will be fine. What order do you propose with bed fertilizing, specifically rose fertilizing, and pre-emergent such as Preen for weed prevention? Is there any danger of overfertilizing if I start with the 13-13-13 and then after I prune my roses I apply the rose food to each individual bush?


Dear K.F.,

Both 10-10-10 and 13-13-13 are 1-1-1 ratio fertilizers, meaning they contain balanced amounts of nitrogen, phosphorus and potassium. Without a soil test indicating specific deficiencies in your soil, either one will do as a guess. The difference is that 13-13-13 is more concentrated, supplying each nutrient in an amount equal to 13 percent of the package weight, as opposed to 10 percent of the weight. So for 200 square feet of mixed-species perennials I'd use four pounds of the 10-10-10 during the year but only three pounds of the 13-13-13.

An ideal program supplies fertilizer to each plant as it enters periods of active growth. To do this, fertilize each plant separately, starting as it begins growth and continuing at intervals during the season. For mixed-species beds full of plants with differing growth schedules, it's simpler to make one, early season, whole-bed application of a slow release product such as Once, Osmocote or an organic biosolid such as manure.

The fertilizer "39-Plus 13-13-13" is not a slow release product, so you should wait until most or all of the plants in the bed are growing before spreading the first dose of fertilizer.

To do the best you can for a group of roses in a bed, don't start fertilizing until they show strong growth. If you use 13-13-13 or another quick-release product, split the annual dose into three or more portions, applying a bit every few weeks between late April and August.

Can you overdo it with 13-13-13 now and another fertilizer later? Yes. You can overdo anything if you don't do the math to figure out the annual dose. Roses are "heavy feeders" using up to twice as much fertilizer per year as a daylily or daisy. The annual dose for two hundred square feet of rose bed -- 25 roses spaced at three foot intervals -- can be twice what a mixed perennial bed of the same size would need. Set aside eight pounds of a 10-10-10 or six pounds of 13-13-13 to mete out to those roses. If you use a fertilizer with a first digit lower than 10 you'd use proportionately more of that product.

Short reports

Cocoa hulls dangerous to dogs

K.H. writes: "In your column you recommended cocoa beans for mulch. Please tell your readers that if they have dogs they should not use this where the dogs can get to it and eat it. At least as far as I have read, this can be poisonous to the dogs."

Cocoa bean hulls are used as mulch, K.H., not the beans themselves.

Dr. Bismack at Berkley Animal Clinic is always willing to help me and so looked into it for us. "My references say that deaths have been reported from animals eating cocoa hulls, though I haven't seen this problem myself. Cocoa hulls contain 0.2 to 3 percent theobromine. That could be a problem for a small dog. A larger dog might not have trouble but then it all depends on how much they eat. For instance your crazy dog, Janet..."

As a dog owner I know that any number of items in a garden are dangerous, including some mulches for chemical constituents, others as choking hazards, blood meal for nitrate, and various roots and leaves for toxins.  As with children in a garden, attention is what's most important.

Plant shortages this year

California nurseries have been quarantined to contain "sudden oak death" fungus, a disease that can reside on over 40 species of plants and kill very large oaks very quickly. California is a major plant producer so if your garden center promised you a certain plant and can't deliver, please have patience. The health of our oak forests is worth it.


Green thumbs up

to an early season attack on creeping Charlie, a.k.a. ground ivy or gill-over-the-ground, if it's running amok in your lawn or garden. After it flowers you'll lose your chance to use herbicides, as the plant develops a chemical resistant coating on its leaves later in the year.


Green thumbs down

to looking the other way while your new lawn goes down over hard packed soil, and just hoping it will all work out. It won't. Stop at an MSU Extension (in phone directories under County Government) for a bulletin on sodding or seeding a lawn, and make your contractor follow it!


 Originally published 4/17/04