Has anything changed? Hotter this year? Less rain? Less or more sun? Change in food? When you say a weak blooming fertilizer, what type and what is 'weak'?

It has been a both a cooler summer in the beginning and extremely hot the past 3 weeks. Originally as the plants required water (about the Feb/Mar timeframe) I decided that I should put them on a regular watering schedule but the soil was remaining too moist so I backed off to my old way of watering only when the soil showed dry. The fertilizer I've been using is the Miracle Grow "Bloom Plus" and I mix it half strength of the recommended strength. We did have a few freezes this past winter but I have bamboo shades I can lower on the pergola and I hung a box fan inside to blow on the plants. It never got below 27 degrees. I have lost plumeria to freezes in the past when I had them in pots but haven't had any problem since they've been in the ground and have used the shades/fan. Two of my seven plants have bloomed this year and normally they all do. Another strange happening is that the new growth on two of the plants grows to about 1-2 inches and hasn't grown anymore in almost two months. None of this has ever happened to me in the past. I've been growing them for years and they have always done so well??