My hydrangea is very leafy, but not producing flowers. Should I be adding something to the soil? This is the second consecutive year and I am totally perplexed. Appreciate any and all assistance. Thank you.
Hydrangeas won't flower well if you are using fertilizer with more nitrogen than phosphorous and potassium. Is this hydrangea in the middle of your lawn receiving lawn fertilizer? Lawn fertilizer has too much nitrogen for promoting flowers/fruit/reproductive growth. You'll get lots of healthy vegetative growth (leaves, stems) but very few flowers. Also, if your hydrangea is in deep, deep shade it won't flower well either. Pruning is important as well as timing of pruning.
Many of the older varieties of garden hydrangeas set flowers that can be killed by bad winters and late frosts in spring. I live in nyc and didn't get any flowers last season. This year I got flowers on one bush and not the other one(different varieties). These plants also flower on previous year's growth. They should not be pruned back because blooms develop on previous year's growth. Pruning in fall,winter or spring will remove flower buds.
There are several varieties of hydrangeas. I am guessing you have one that only blooms on old wood. Use one/two tablespoons of Holly-Tone fertilizer in early May and once again in late June. I also recommend putting your used coffee grounds in the soil, hydrangeas love that. Do not fertilize after August. In the winter after a good frost, cover the plant very generously with mulch such as straw/hay (I am talking about a big mound to protect all the tiny flower budlets on the old growth wood). Sometimes a very hard winter can not be protected against and you will have a bloom-less year. Avoid pruning completely. After all danger of frost has passed, remove the mulch so the sun can penetrate. Do not over-water the plant. Droopy leaves are normal in afternoon sun, the plant will perk up the next morning, no need to add water.
I can share my experience with you. I have hydrangea in my courtyard where is gets sun for only part of the day. I have had them for 4 years and have not really fertilized them much (I probably should). I had flowers all 4 years and they are particularly doing well this year. I did prune the dead flowers and I was told that they should only be pruned AFTER new growth starts appearing below the dead flower and not before. This is something you should be aware of as well and may not be directly related to what you are experiencing.
You have to tell us what cultivar it is. The most common issue is that hydrangeas bloom only on old wood (save for "Endless Summer" and a few others). So if the plant was pruned back you will get no blooms that year. Leave it alone and see how it does. If as you say, you removed the old canes, that right there is your problem.