What's the knack?

SamBevington

I've got 4 new borders in the making, 2 edging a path 10 m long, 1.5 wide and 2 semicircular 3m deep 4m wide. Over the year I've invested in plugs/young perennials and have over 300 (cough - don't tell the OH!). I've started to plant up with evergreen shrubs, trees, roses; looking good but I popped a drift of 7 young coneflowers in and they look so pathetic with just one stalk/flower. How do GC do it? Is, say a healthy specimen that you by for 7 quid, 3 plants in a pot or one that's a couple of years old 🤔 ?

Fairygirl

In general, a plant in a 6 or 7 inch pot should be a mature plant. However, it also depends on the outlet you're buying from and when the plants have been potted on. Many unsold plants will be 'moved on' for the following year for example, so the rootballs won't be filling that, as they might have just been divided. That happens more often in nurseries. GCs tend to just sell stuff off cheap, or leave it on shelves.
Conversely, most perennials also need dividing every few years, so you might be buying a plant at that stage, rather than one just divided. 
Some perennials are also just short lived. 
It pays to look closely at the plants when you take them out their pots, especially in spring, to see what stage the plants are at 

CharlotteF

All that ^^^

When you're paying out for a 2l+ pot, you're paying for the compost, labour, water, feed etc taken to grow that young plant on. The downside being that often, particularly in a new border where all plants are at similar stages, the bigger plants actually take longer to adjust to their new conditions and start growing away than the younger, cheaper ones.

Your young plants won't stay small for long come next season (caveat being the only time I've tried to grow echinacea it was devoured by slugs, so take care in wet spells!). All being well, they'll get their roots down over winter and get ready for a big flush of healthy new growth in their new home in the spring. 

raisingirl

One trick with younger plants is to use seed sown annuals that look similar as a filler for a year or two while the perennials mature and fill up the space.