I have an event coming up at my house. can I fertilize agastashe and echinacia hybrids or will it be too much for them? they are new and I want to stimulate growth.

As for the Echinacea at this time of year you want root growth not to push top growth if you want them to overwinter. Not really heavy feeders , try some bone meal. If just planted you could try some Quickstart.

Here's an idea: When we had a big back yard event, I purchased new plants in bloom a day or two before and set them out in the garden for color. They went well with the foliage of my bedding plants that weren't in bloom at the time.. I even bought flowering plants in the party color themehat won't grow in my yard as center pieces just for a touch of color Then I gave them away to my helpers.