Trees don't generally need fertilizer. In fact, fertilizer probably kills more trees than it helps. What makes you think yours are in need? Unless your soil is deficient in some nutrient, a good organic mulch is all you need. If you think there is a problem, get a soil fertility test done.

You can do a search of the forum for more info if you like, but I think the above information is a general summation of what you'll find. This question is asked over and over and over by non-regulars.

Horticultural business supply houses that also sell to the public. Look under Grower's Supplies and the like in directories.

I guess the reason 19-6-12 was suggested is arborvitae tissue has an NPK ratio of about 3-1-2. I don't think it has to be the scotts osmocote fertilizer. Anything with the 3-1-2 ratio will do. If you can't find any, Something like espoma Holly Tone or Rose Tone will probably due. The main thing is arborvitae require N more than anything else. The good thing about Holly Tone is it's naturally slow release and you would have to be very dumb to over do it. You don't have to mix it in. I just scoop out a cup or so and dump it near the base of my plants. Long term, you probably won't need to fertilize. if you fertilize your lawn, they'll take up N.

I'm with brandon. Save your money.

Dan

brandon, i was told by the supplier to purchase the osmocote 19-6-12 and feed it to the trees in about a month. I'm asking here because i know you guys know much more than i do about this. i just want these boys to grow STRONG and HEALTHY ASAP to prov1ide a privacy screen from those neighbors who can't seem to mind their own business.

I see that formulation greening up the plant too quickly but making the client think 'wow great plants'. If you want them to grow strong and healthy dig an excellent hole, plant them properly (if B & B not too deeply - take soil off the top til you get roots), make a large watering well and make sure they don't dry out then take the wells down in fall. Out there your soil should be fine in general. If you insist on purchasing fertilizer for some reason (not necessary in general) purchase a product that will feed the roots. I won't name names because you should spend the money locally at a local business instead (like the watering hole on the corner).

Dan

All depends on what nutrient availability situation is on your particular site at this time, something nobody who has not sampled your soil and had it tested can make informed comments about.

if you use a time release.. that is not timed for your zone.. you could be dumping fertilizer too late in the season .. and actually cause sever harm in some zones ...

unless a soil test indicates something lacking in the soil.. trees need NO FERT ...

all they need is PROPER water ... to get ESTABLISHED ... and once they are such.. they will grow roots out into the lawn and steal whatever fertilizer you put on the lawn ... which in my case.. is just the mulched grass clippings..

they are trees.. NOT CHILDREN.. they dont need to be fed.. they dont need to be washed.. nor schooled.. or potty trained ...

forest cover about 75% of the face of the earth.. with no help from man ... why do yours need help???

it really boils down to the place that got your money for the trees.. also wants your money for the stake.. and your money for food that isnt necessary .. and for bug spray.. even though you dont have bugs... just how much of your money do you want to give this guy .. you really neednt pay for his boat.. and his kids college tuition ...

just water them PROPERLY .... and they will do just fine.. and mulch them whiel you are at it ..

ken

I think most of your questions have been covered above, but just to reemphasize the importance of mulch, I will repost my list of mulch benefits. When you apply mulch, install a layer of organic mulch (bark chips, pine needles, shredded wood, etc) about 3" to 4" thick out as far as reasonably possible from the base of each tree. A minimum distance should be the tree's dripline. Never place the mulch up against the trunk. Leave a couple of inches of gap between the trunk and mulch to reduce possible complications of disease and pests.

Benefits of Mulch
-improves soil fertility and texture as it breaks down,
-prevents germination of many weed seeds,
-reduces competition for food and water from grass and weeds,
-reduces erosion,
-helps to maintain soil moisture during dry periods,
-often aids drainage by preventing surface crusting and sealing,
-can keep roots cooler during hot summer weather,
-can help to moderate soil temperature fluctuations,
-reduces frost-heaving,
-reduces certain soil-borne diseases by preventing soil and fungi from splashing onto foliage,
-prevents damage from mowers and trimmers,
-and improves the look of the landscape.

If I may add to brandon's excellent list:

o You may get edible mushrooms in the mulch. Yum!

Dan

But how do you know if they're edible?

That depends on learning how to identify them.

really? LOL

We have 30 Green Giants lining our driveway that we planted 3 years ago. They were 2-3' tall then and are now 7-8' tall.
I was told to use Black Kow composted manure for a fertilizer by the farm that sold us the trees. Our soil is rather sandy and well draining. Is this a good idea ?

I've been told over and over that the Giants will grow 3' a year with proper drip irrigation. TRUE...FALSE??? Anyone? I just today 11/27/15 planted 40 of em' to ide the farm next door.

I used a 9" post hole drill on my tractor 18" +/- deep with root ball even to slightly just below the surface. I filled in the hole up to where the bottom of root ball touches. Hope I did right.

Many business establishments just happen to have exactly the fertilizer "your new plants need". Amazing, isn't it? Nitrogen is the nutrient almost always in short supply in any given system but......that's misleading. That simply does not mean there's anything inherent about the site that is preventing what we would consider normal or proper growth. What it does mean is top growth could and likely would be boosted by the addition of nitrogen. In a newly-transplanted tree, is boosted top growth the proper goal? I think not. What the plant needs in order to do everything it needs to do is an adequate root system so as to secure-above all-water. To secure enough water, the roots need to grow. In most soils in most situations, the roots will grow faster if there's not all kinds of nitrogen present. It is for this reason that most modern planting regimens call for no addition of mineral nutrients (fertilizer) at planting.

Now a year or two or three down the road, presumably these root systems will have regenerated themselves. At this time, a mild addition of fertilizer will probably not hurt anything. Is it needed? No, and that's a vague notion anyway.

Some will say that a soil test must be done to know what's going on. Yet for the vast majority of landscape plants, actual requirements of the main and micro nutrients are a complete unknown. Corn and soybeans-yeah, we know exactly how many pounds of nitrogen per acre is required by a given corn variety. Arborvitae? Absolutely no such data exist. I'm not saying fertilizing established plants will lead to the end of horticulture as we know it, I'm saying it is complete fishing in the dark. Be leery of hard facts and claims in this area-they are surely bogus.

+oM

And have a guess at what the most expensive fertilsers in the universe are for - yep, put a cannabis leaf on any old bottle of NPK (and some 'psychedelic' graphics) and charge WHATEVER YOU LIKE.

No doubt!

"...(F)or the vast majority of landscape plants, actual requirements of the main and micro nutrients are a complete unknown. ...Absolutely no such data exist."

The group has had this discussion before. I will leave it at...I completely disagree with that statement. I believe (don't remember exactly how far we went with it) that last time I gave references that would disprove that claim, but won't take time to do it again.

Brandon, I do know that of which you speak. It is a good representation of the difference between growing in a soilless medium and having to literally supply all nutrients, and the much more common paradigm faced by gardeners everywhere, that of planting in soil. I too will leave it at that but we're talking about two different things. The nitrogen example is most telling, in that-yes I am now repeating myself-virtually every "system" could easily be shown to be nitrogen-deficient, simply because a growth response could be elicited by the addition of more N. Where that breaks down then is the fact that if that factoid were then applied to every bright green forest on earth, they would all be found to be "nitrogen-deficient", truly a crock.

+oM

This forestry handbook says what soil nitrogen level from low to high the presence of each species used indicates. Means somebody did the research to find this out. And was able to find it out.

Table of Contents

Tables

Figures

Acknowlegements

1. Introduction

Background

Scope

Format

2. Basic Concepts

Ecosystem, Vegetation, and Site

The Ecosystem Concept in Forest Management

Site Diagnosis

3. Concepts and Methods Related to Indicator Plants

Plants as Site Indicators

Choice of Objects of Plant Indication

Indicator Values of Species

Choice of Indicator Species

Indicator Species Groups

4. Site Attributes and Indicator Species

Climate

Indicators of Climate

Soil Moisture

Indicators of Soil Moisture

Soil Nutrients

Indicators of Soil Nitrogen

Ground Surface Materials

Indicators of Ground Surface Materials

5. Indicator Plant Analysis

Individual-Species Method

Spectral Method

Index Method

6. Distribution and Ecological Characteristics of Indicator Plants

http://www.ubcpress.ubc.ca/search/title_book.asp?BookID=1443

I KNOW there is shedloads of N in mine because of the 6 foot nettles...and hugely abundant chickweed.

Camp, keep in mind, a lot of phosphorus leads to internodal stretch. Everyone seems to think that P is "bloom food' or some other species of nonsense. It is directly involved in an array of factors, of course, but often overlooked is its role-especially when extra-abundant-in causing unwanted stretch.

Emb, I don't doubt for a minute that a range of values can be ascribed to a variety of plants. In fact, that supports my view completely-that these species and cultivars exist across a continuum of soil nutrient conditions, not some imagined (and mandatory!) sweet spot. All biological processes operate in a system replete with feedback loops, one facet influencing another and another....one compensating for a lack in another, and so on. Were it not so, we would not have the type of world we see before us, leastways in the non-bulldozed areas.

+om

"Yet for the vast majority of landscape plants, actual requirements of the main and micro nutrients are a complete unknown."

"I don't doubt for a minute that a range of values can be ascribed to a variety of plants."

I read these statements as near opposites. In my opinion, we know how to calculate an optimal level of a given nutrient far more accurately than would be practical to apply in a real-life situation. The requirements are known and understood but are complex and unreasonable to apply in an exacting fashion. Of course that doesn't mean we just throw up our hands and forget any soil analysis.

Even nutrient requirements for crops (e.g. corn and soybeans) are far more complex than just adding x number of lbs of fertilizer to the field. Practically, we can arrive at a good guess that will cover most situations, but the same holds true for our landscape plantings.

Heh, I see equivocation in your latest too, Brandon, all the way from the statement that "we know how to calculate an optimal level" to "(the requirements) are unreasonable to apply"...which leaves us exactly where? And then there's the nitrogen problem which, far from an annoying detail, sits at the center of this debate. Nobody who understands plants and soil nutrients will fail to grasp that for the most part, this is a nitrogen issue, first and foremost. Yet, that nutrient is never tested for, for reasons already given-it's instability in the soil and the difficulty of pinning down just how much of the stuff is there. Nobody in the practical world is going to tell you how much nitrogen your soil has available for plant growth, while at the same time, this is the most pertinent datum. BTW, I never said don't test soils. I said take a large grain of salt with you when "interpreting" the results, and have more salt handy when you go to apply these results with Thuja....or Berberis....or Carya....or Syringa...or Hemerocallis....or......ad infinitum. It's all guesswork dressed up in nice lab clothes.

Meanwhile, the vast majority of soils where the vast majority of folks are gardening have adequate levels of most important nutrients for the vast majority of genera likely to be being grown. The intimation that success is right around the corner if only one reads lots of soil test results and then "applies" these results is in most cases, a red herring.

+oM

I don't get the "equivocation" thing. All I'm saying is that a great deal is known about the nutrient needs of landscape plants, and, that we don't have to take EVERYTHING that is known into consideration when making decisions about adding nutrients.

While I'm not ascribing this to you, Brandon, I just don't want to leave folks with the mistaken (in my opinion) belief that optimal nutrient levels across a wide spectrum of landscape plants-not turf grasses, and def. not corn and soybeans-I always use those because they cover million of acres and have been studied to death-are necessarily known or understood, and more importantly, that there is any practical way to apply said knowledge even if it did happen to exist....and first and foremost, that the nitrogen problem easily eclipses this whole deal, in that that nutrient is never measured in any but the most high-falutin soil analysises, and immediately after said measurement would have theoretically been made, the value would have changed anyway. And that that is significant because despite all the hoopla about some magic elixir of micronutrients (yes, occasionally important), it is nitrogen that is the limiting factor in virtually every system. And we don't know a dern thing about it!

As I said much earlier, one way to make the determination that some nutrient or other is "in short supply" is to add it to the system and then observe a growth response. But where that falls down is the fact that virtually every system could see a growth response if N is added. We know better-both of us-than to think that this "proves" that N was lacking. And further, we both know that adding N can lead to problems. I just don't want folks to read something here and then think there's some idealized spot on the continuum for these various nutrients, when in fact, it is the entirety of that continuum that is "the sweet spot". Plants have had to deal with this forever, and they do so very well.

+om