Learn the rules of fertilizing, the gardener's game of
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?
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.
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
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