My yard is a typical small to medium city of Toronto yard.
I live about a block north of Lake Ontario in Mimico (part of Etobicoke), in an area that was once marsh land.
The soil is heavily clay.
Being close to the lake creates a microclimate that is cooler in the summer and a little warmer in the winter.
When I first got my property I dug deep and amended the clay with decent soil.
The plants seemed to appreciate that and I’ve had great success with a lot of unique plants.
It is now a fairly mature yard, dense, very natural looking with tall trees, understory trees and shrubs filled out with smaller flowering plants and ground covers.
Great care has been taken in understanding what would be the best exposure and planting situation for each plant… and so far they seem to be thriving.
A lot of the plants are acid loving (rhodos and azaleas) so the soil has been heavily amended to create a peaty, acidic base for them.
Just wanted to let you know a bit about where everything is growing.
I’ve never really bothered to fertilize anything since they all seem to be doing well… but after 25 years you’d think the nutrients in the soil might be depleted.
So I think it’s time to feed all of this.
I have a pile of fertilizers I’ve never used and am pretty overwhelmed with how and when to use to use them.
So this is why I’m reaching out to you today.

Not sure how to approach this so I have lists of the fertilizers, plants to be fed and some specific questions.

First of all I think I understand what N,P and K do.
Pretty sure this is what they do:
N greens leaves up – but does it promote more leaf growth?
P promotes root, fruit and bloom development – but can it be used on trees that don’t fruit or bloom?
K strengthens plants to resist disease and keeps them vigorous during drought and infestations – but I’ve read that the soil already has lots so is it necessary?

Am I correct?

I have a pile of fertilizers already, which is great, but am not sure which ones to use on which plant, shrub tree.
One of the fertilizer’s instructions said “use this as part of your regular fertilizer protocol. I read that and thought… I never had a fertilizing protocol. Should I?
If so what would that look like?
Any thoughts on a fertilizing protocol through out spring, summer and fall?

Forgive me but I’ve listed all of the fertilizers I have below so you know what I have.
Most seem N heavy.
I read the labels, get what they do but then I’m confused when the combos of numbers are similar.
Or when one lists that it’s good for trees, shrubs …and cedars?… so initially I think I can use it on all trees and shrubs (like a Serviceberry for example) until the mention of cedar… which makes me think it is more for evergreen trees like cedars.
I also don’t want to kill any plant with the wrong fertilizer or combo of fertilizers… or is that possible?
Here’s the list:
4-12-8 ( I know this promotes flowers in rhodos and azaleas)
Would the 20-20-20 be the best all round?

Again, for clarity I’m just going to list what I’d like to feed.

List of shrubs/trees I want to fertilize:
Jack Pine (mature, 20’)
Japanese Upright Yews (mature, 15’)
Japanese Maple (mature, 20’)
Mountain Ash (mature,25’)
Fairview Juniper (20’)
Weeping Japanese Maple
Mugo Pine (mature 5+’)
Magnolia (Susan?)
Sweet Bay Magnolia
Honeysuckle (old and mature)
Hicks and Hills Yews
Cedar (pyramidal)
Oregon Grape
Viburnum Lantana – Wayfarer Tree
Viburnum Plicantum
Balsam Fir (very tall – 70’, very scrawny, needs some love)
Forest Pansy Redbud (newly planted last fall, about 9’)
Ground cover junipers
Various grasses and ground covers: Ajuga, black Mondo grass, Japanese Forest Grass, Purple Coneflower, Rugutso rose etc.

General questions:
I’d was going to feed everything (evergreen and deciduous) a 30-10-10 to boost leaf/needle grow and green everything up. Does that make sense?
I want to feed the 30-10-10 to my rhododendrons and azaleas for the leaves but want to use a 4-12-8 also on them to encourage flowers. Will that be a toxic mix?
3) I have a weeping Japanese Maple that, for some reason this year, has not filled out like it normally does. It’s very bare. So I was going to give it a blast of the 30-10-10 thinking that, even though the foliage is red and not green, it will boost leaf production. But I’m unsure. Would the 20-20-20 be a better overall for it since it seems weakened?
4) Is there a perfect all round fertilizer? If so what N-P-K combo should I look for?

I think that covers it.
Apologies for so much detail but I figured you’d need to know the lay of the land before you can answer.
Looking forward to your thoughts.
Thanks. – Andy Brokenshire (416-252-2680)


Wow! What a list of fertilizers.

Let’s start by saying the Toronto Master Gardeners are big fans of the use of organic materials to amend your soil. Organic materials have more benefits that just providing the 3 main nutrients as listed on most chemical fertilizers. Below is article done in partnership with the City of Toronto on the benefits of using organic amendments.


Except for natural mycorrhizal fungi that form a symbiosis with the growing roots and found in many plant starter products, an organic amendment as noted in the article above be all that you will need.

Good gardening.