Reilly, are you talking about Vitamin B1?
Because, if you are, it turns out that it doesn't do much more than plain water.

Jeri

Hi remontant

If you are thinking of mycorrhizal fungi I don't think that will do any thing either way for your roses. If they are fairly newly planted it can make a big difference, but when this type of microorganism once is established that is enough (I have read that it on average take about four or five years before it establishes if not added in planting hole). There are other types of microorganisms like beneficial bacteria and tricoderma fungi that with advantage can be added to the soil around the plant. The sort that naturally exist in compost, cow and horse manure.

Your roses are probably just fine, but if you feel the need something, a fertilizer with low to no nitrogen can be added. Seaweed have in some trials showed the ability to make plants more winter hardy and healthier.

Thanks, everyone. The product I used this spring was Green Light brand Root Stimulator & Starter Solution: 5-15-5 for newly planted flowers, shrubs, and trees. Sounds like with that 5% nitrogen, I better not apply now or in fall.

Back to the compost pile! Thanks, everyone, for your help!

Your roses would really like to have a second application of fertilizer when they are in the first flush. Then they are looking for nutrition for further growth and flowering. The liquid fertilizer have not as long lasting nitrogen as some solid types. It is ok to apply some now. Your roses probably needs it if your type of fertilizer is not a slow release type that lasts for six months, like some osmocote do.

I use Rose Tone (granular) monthly through spring and then stop the first of June. (Part of that is also because I don't want them wasting their flowers on the Japanese beetles! ):-/ It sounds like another slosh of the 5-15-5 might be OK on the newbies (which aren't blooming anyway). Thanks, Taoseeker!

I'm wondering about Rose Tone for a second application but it is so dry here. Anyone have an opinion. I am still watering but nothing beats some rain.

Carla