"Bloom Booster" has become a generic term for "high in phosphorous". Miracle Gro's version is something like 10/50/10. I don't know of any controlled test results with high phosphorous formulas, but I'm inclined to avoid them for the following reasons:

1) I read most of the rose exhibition articles in the American Rose magazine and I've never seen a recommendation for a bloom booster fertilizer. I did read one recommendation suggesting that a "blip in phosphorous is beneficial just as the flower buds are set". The extra phosphorous recommended was actually very small and the intent appeared to be to improve bloom quality rather than quantity.

2) Excess phosphorous is the surest way to destroy the useful micorrhizal fungus which colonizes the roots of roses.

3) Commercial growers of roses for cut-flower production typically feed their roses with fertilizers having close to the 3/1/2 NPK ratio which is present in the tissue of roses and most other plants. I have read several articles on soilless greenhouse rose culture which demonstrate that if the nitrogen is optimal for a rose, feeding more than 1/3 that amount of phosphorous (as per the 3/1/2 ratio) does not result in increased phosphorous uptake.

4) Excess phosphorous tends to build up in the soil and this can restrict the uptake of other nutrients, such as iron.

So far as comparing Miracle Gro to Bio Tone, Miracle Gro is a complete, reasonably balanced fertilizer. Bio Tone contains only nitrogen (and soil microorganisms) and is intended mostly as a starter for new plants or as a supplement to a balanced fertilizer.

"Excess phosphorous is the surest way to destroy the useful micorrhizal fungus which colonizes the roots of roses."

Hi Mike, do you have any websites you can share that elaborate on this further. Or books - I'm willing to shell out the $$ for a good book on the subject. : ) I would love to learn more about how all the different nutrients interact and affect our soils. Thanks!

I've only used the Bloom Booster in container plantings, mostly annuals. Nothing died and they did look better. Maybe I will experiment with a few roses I have in large containers.

Diana

Diana, the linked article below is from the Colorado State University Extension Service and it has a number of links and references. As I understand it, the fungus feeds phosphorous to the rose and the rose, in turn, feeds carbohydrates to the fungus. If the soil level of phosphorous is high enough for the rose to obtain its own phosphorous, then the rose stops feeding the fungus and the partnership is dissolved. I suspect that for the small scale home rosarian, for whom fertilizer is a relatively minor cost, the major advantage of the micorrhizae is a far more extensive root system on the rose plant which may then require less water and a tougher, more resistant rose.

Here is a link that might be useful: Micorrhizal Fungi and Phosphorous Levels in the Soil

Mike, thank you so much for the link and additional info. I glanced at the link within the link - lots of great info, too. : )

Diana

I got a notification that Ha-Kim Xis liked my comment on Bloom Booster but I don't see that name here. It's not called that (Bloom Booster) this year but is the same stuff I had the last couple years that has Miracle Gro Shake and Feed then Bloom Booster on the container. I couldn't find what I thought I was supposed to get and this is working. Anyway I just got a new supply in a container with a handle and spout you pour the granules from, looks like the same stuff as before. Only I'm not using it on my roses. It is working well to keep my tulips coming back, learned the idea from somebody on the tulip forum. In the spring after the tulips bloom cut off the stalks but let the leaves die naturally. The fertilizer helps the leaves which must manufacture food for the bulb(s) for the following spring. Sprinkle like it shows on the container with the granules (looks like time release and maybe Osmocote would work, too). Anyway, just let them alone and in the fall and sprinkle another application. I can use it on regular flowers, too. If you don't need a whole lot, it works well and I like the sprinkle time release feature rather than mixing up a solution in the sprinkling can but maybe either works just as well.

Here's a article on the subject....

http://www.rose.org/phosphorus-fallacies-too-much-of-a-good-thing/

Any bloom booster-- the middle # being very high such as that 10/50/10 is typically used for annuals I believe. I would not use that on roses.

Adrianne

Miracle Grow reformulated their Bloom Booster last year, it's now 15-30-15.