Hum, personally I would never use a fertilizer with such a high P. I have had problems in the past with my plants because of this..Instead I would find a formula lower in P and even lower in N.

"To induce more prolific flowering, a reduced N supply will have more and better effect than the high P bloom formulas. When N is reduced, it slows vegetative growth without reducing photosynthesis. Since vegetative growth is limited by a lack of N, and the photosynthetic machinery continues to turn out food, it leaves an expendable surplus for the plant to spend on flowers and fruit. Plants use about 6 times more N than P, so fertilizers that supply more P than N are wasteful and more likely to inhibit blooms (remember that too much P inhibits uptake of Fe and many micro-nutrients - it raises pH unnecessarily as well, which could also be problematic). Popular "bloom-booster" fertilizers like 10-52-10 actually supply about 32x more P than your plant could ever use (in relationship to how much N it uses) and has the potential to wreak all kinds of havoc with your plants".

Just info I wanted to share from a very experienced container grower who has done wonders for many trying to produce blossom on their plants..

Woowww that's quite shocking as I read on a website for plumerias and all they show for plumerias is high high P.

Which fertilizer mix would you recommend?

This older thread might help you decide..

I myself use Foliage Pro, epsom salts,and even put a bit of dynamite in mine...Dynamite was prescribed for mine by a well known plumeria grower...

Everything works well for mine..

Bill, or tdogdad by his sreen name, has some great advice in older posts..Just do a search in the search field and type fertilizers for plumies" and you might catch a post from Bill too...Good luck

Here is a link that might be useful: fertilizer

How long are the cuttings that you feel are too large? In my experience, larger cuttings root faster and more reliably. If they are truly too long for you, just cut them from the bottom to a length you feel is appropriate. I wouldn't cut them shorter than 14-16" personally. Shorter cuttings may root, but I have few failures with cuttings of the above length.

Also, I emphatically agree with the recommendation to avoid high P fertilizers. Commercial growers that I correspond with don't use them. Most use a balanced fertilizer, or one with reduced nitrogen . I use a 10-10-10 during the spring to get the plant started, then switch to a 4-10-10 during the summer, and a 0-10-10 in the fall.
Mike

I am moving away from the Bloom Buster type fertilizers as well. As soon as it warms up here in N/Fl I am going to start things off with an liquid organic fish emulsion 3-2-1, then a balanced 10-10-10- granular and then for the summer and fall back to a liquid organic 0-10-10. The liquids will be used for periodic root soaks and foliar sprays. Most of Plumies are in 3 & 7 gallon black landscape containers. I would welcome any other thoughts on my fertilizing program ~