I planted 4 New Dawn climbing roses in June. I think I over fertilized (2x) with Miracle grow. One stem bloomed but the rest is just weak green growth. Can these be saved.
Thank you for contacting the Toronto Master Gardeners concerning your New Dawn roses.
The following information on rose fertilization comes from some of our earlier posts:
” Most roses are what are known as “heavy feeders” which means that in addition to providing them with high quality soil, amended with compost and well-rotted manure (which you have on hand), you should be applying fertilizer to help them grow vigorously and to bloom well. The easiest way to do this is to use a granular fertilizer suitable for roses. These can be found at most garden centres. Your slow release fertilizer should work well – the package directions will tell you whether it is recommended for roses. It goes without saying that you should follow the directions on the package when applying any fertilizers.
The American Rose Society has a clearly written guide on fertilizers for roses: https://www.rose.org/single-post/2018/03/20/a-fertilizer-primer-what-s-in-that-rose-food that you may find helpful. It is important not to over-apply any fertilizer, and particularly blood meal, as leaf scorching can result. Watering before and after fertilizing is important“
Just as an over-fertilized perennial will reward gardeners with excess growth that flops over and becomes leggy half-way through the season, so can an overfertilized rose lead to leggy stems, and can also affect bloom performance.
Healthy rose stems only need the spent flower head removed, but weak spindly stems need cutting back to encourage new growth. Prune spindly stems back to where they are at least pencil thick, even if it means removing almost the entire shoot.
Garden Making has an excellent article by Judith Adam on How to Prune Roses. It discusses how to know if the wood is dead and when to remove it, whether you should cut green living wood, how to properly make a pruning cut, and it also has a rose-by-rose pruning guide.
The Toronto Master gardeners also have a Garden Guide on Pruning Roses
Good Luck with your roses.