I doubt spraying blooms with fertilizer will be as effective as spraying foliage, although I suppose it can't really hurt too much provided the fertilizer mixture is not too strong.

You need to determine first why your blooms are falling off. Immature plants? Newly-rooted cuttings? Spider mites or thrips?

Fertilizer certainly helps the plants grow and become healthy. And that in addition to healthy roots will eventually lead to good bloom -- along with warm temps, moisture, sun, etc.

For the love of your plumies, don't use the bloom booster for foliar application. The phosphorus will burn the leaves right off the tree and phosphorus in general can hardly be taken up, if at all, other than by the roots.

If you want to add some mojo by spraying, use a micro-mixture and/or epsom salt mixed in at a low concentration, especially when there are deficiencies. Otherwise, you'll be better off sticking to traditional fertilizing methods.

What do you mean with "keep the blooms on"? Are the buds dropping pre-maturely or do they not open? The life cycle of a single bloom once fully open is anything from 2-5 days in full sun, more if not as hot or with some shade provided; depending on the cultivar,

I will stop spraying with the bloom booster fertilizer. I did it a couple of times, very lightly, and booth times it rained later in the day. When I say the blooms drop, I actually mean the buds. They start forming and then they fall off. Not on all of the plants, just some of the less commom varieties. I believe the one that is giving me problems is a "lani" . I just saw some pics someone posted and realized that it is the same. I have a yellow one and a pink one that produce flowers nicely. Also I have a red-orange-ish bloomer that produces lots of inflorescences and a few flowers on each inflorescence , but the the majority of the buds don't mature, so that is why I tried the bloom booster spray. I live the Atlanta Ga. area.