Q.How to keep fleabane growing too tall
I have fleabane, a lavender ray, yellow center wild flower. It can grow to 3 feet tall. I would like to have it at least 1/2 that size so as to create more of a carpet effect. When could I cut it and yet allow it to produce blooms in fall? It is a great last meal before winter for bees, butterflies and moths.

You can cut it back by half but wait until after the first flowering period. Cutting the fleabane back in this way will encourage a second round of flowers. Afterwards, it can then be cut to the ground in the autumn.
For more information on fleabane, please visit the following link:
https://www.gardeningknowhow.com/ornamental/flowers/fleabane/daisy-fleabane-growing.htm