Depends on the specific product but by and large, no :-) Most contain some sort of growth hormone, some have B1 and other nondisclosed and rather mysterious additives (that may or may not do anything) and some are just a root booster fertilizer with a higher concentration of phosphorus, often sold as a 'starter' fertilizer.Of any of these I would opt for the starter fert first Here is a link that might be useful: root stimulators - fact or fiction

Root stimulator comes in flavors/potencies that I am going to call low, medium and high. I would recommend using the low potency on azaleas/rhodies and the boxwoods as they are both shallow rooted. Too much root stimulator or too much of the wrong type could cause a problem as you describe but it would probably not be localized to just the top of the plant. The boxwoods may also be having a bad case of transplant shock and-or a moisture issue since it is quite warm nowadays. Make sure they are well mulched and that the soil is not wet and not dry. Test your clayish soil using the finger method... insert a finger to a depth of 4" and determine if it feels dry, moist or wet. You want to avoid wet or moist-dry periods. Do not fertilize this year if the potting soil came with those round fertilizer pellets (otherwise, use a 10-6-4 NPK Fertilizer). Applying too much fertilizer to these shallow rooted plants can also cause browning (or yellowing) of leaves but it would not be localized at the top of the plant either. There are a host of other problems like root rot which causes dieback from the top of the plant, vole damage, etc. By the way, some leaf loss is common when planting them; I do not know if in your case the amount of leaf loss would be considered a lot or "ok" though.

Very interesting information! I must admit I am brand new to the gardening world- learning as I grow! I purchased the root stimulator last year upon advice from an associate at a local and what I consider a trustworthy, family-owned nursery in town. That being said, I assumed he knew what he was doing and bit the bait! Thanks for the input that it is a waste of resources! I heard the same thing on the hydrangea forum. We purchased our home in Athens a year ago. I discovered multiple beauties growing in my yard once spring of last year hit! Hostas are very happy here under a canopy of beautiful white oaks! I had to relocate several of my friends this year. I learned the hard way that our neighborhood deer eat hostas like candy! So, it sounds like what I am hearing is to leave them alone as long as they are in happy soil and getting plenty of water? What should I fertilize with if anything?

Always free to disagree Frank but relevancy plays a role. So based on the VT study on turf grasses that you linked (corrected link below) how much of each product and how often would you recommend using them on tomato plants? I note that the article does include the warning that I addressed above "One should be aware that most of the biostimulants are hormonal in nature and excess applications could be harmful to plants". I also noted the stress the research gave to using only biostimulants derived from very specific sources. For example: brown seaweed prepared by alkaline hydrolysis from Norwegian or Nova Scotia waters Source of such product? Then there is the whole discussion about the effects of antioxidants and free radicals caused by stress in turf grasses and how these biostimulants might reduce those effects. Yet when one looks at the studies done by NIH (National Institutes of health) on the effects of stress in broad leaf plants like tomatoes we find very different results - minimal formation of antioxidants and free radicals. the leaf superoxide anion and hydrogen peroxide concentrations in the transformed tomato plants did not alter much, suggesting a well regulated formation of free radicals suppressing oxidative stress in them. Effect of water withdrawal on formation of free radical, proline accumulation and activities of antioxidant enzymes in ZAT12-transformed transgenic tomato plants. So if the antioxidants and free radicals are not affected in tomato plants dosing them with biostimulants, even in safe amounts if known, provides little to no benefit as it would with grass. That brings me back to your assumption: "it probably extrapolates to most plants." and there is the problem. Grass is unique in the plant world in many respects. It is a monocot - different vascular tissue, different circulatory system, different fibrous-only root system, and no cortex. Tomato plants are dicots - woody stems, ringed vascular tissue with a cortex, reticulated veins, taproots . So one can not accurately extrapolate from tests results on grass to tomato plants. Hope this helps clarify some things. "some Dave on GW who for what it is worth, has been in the nursery & landscaping business for more than 50 years" Here is a link that might be useful: Questions and answers about biostimulants