Posted: 21/05/2017 at 11:36
One thing to bear in mind too, is that when plants are crowded, they're more vulnerable to pests and diseases. Good air flow around many perennials is important. Like many people, I don't always follow my own advice on that one though
Your own climate and soil conditions also mean that some plants will grow bigger, and quicker, than others. Whereabouts are you and what kind of 'weather' is the norm for the area? I'm guessing you might be up here as you use the word wee!
The hydrangeas will probably have suffered a boit of cold - frost or wind - that many areas have had recently. nothing much to worry about. They are better in the ground though - easier for them to get the moisture they normally require. There are lots of evergreens and structural plants - phormiums, hebes, carexes, osmanthus, viburnums, to name but a few. Again - depends on soil and aspect, and your own personal taste