Rule Of Thumb

Hi All.
Do not know if you read my post in the Beginners section (frustrated) but just wondering when you come to plant your perennials do you follow a general rule for planting distances between plants.
A long time ago I purchased a "ready designed" perennial border package which was my first plunge into gardening. At least two things I did not take into consideration 1.Not all the plants delivered were suitable for my soil and so some perished, no doubt some also were not really hardy. 2. I really had too many for my border and did not take into consideration the size of plants when they were mature. The result was some plants like the Michaelmas Daisy overrun the others.
I just read the two bits of advice on the web at bottom. I think if I was going to say plant 2 plants that both grew to 2 feet wide when mature I would say plant them 18" apart rather than the 1 foot also suggested. I would until they mature fill the gaps with annuals?? Just wondering what way you proceed with your planting. My border is only around 4 x 16 feet and South facing so after initial planting of perennials it would not take a lot with annual plants to fill in the blank spaces.
Peter

“If you can't find information about a specific plant, a general rule is to space small perennials 6-12 inches apart, 2-3-foot-tall perennials 12-18 inches apart, and taller perennials 18-36 inches apart”
“As a general rule, allow at least one foot between each clump.
Even with generous spacing, most perennials will need to be divided from time to time and the clumps reduced to a manageable size. Because it may take three to five years before plants fully mature, providing this much initial space can leave you with a relatively sparse garden for a few years.

When you are faced with this situation you have a couple of choices you can plant at half the recommended distance so plants fill in quicker and later transplant them at the correct spacing.

Or you plant at the recommended spacing and interplant each year with annuals to add color and interest until the perennials reach mature size”

 

I work on a similar system, I do look to see height and width, when mature, I also try to, as you say, space out my perennials and fill summer gaps with annuals.
I am really trying to fill my borders mostly with perennials, a mixture of evergreen and herbaceous, and try to space them so the evergreen are not all in one area, and some areas look bare all winter.
Then you have height to consider, some ie: delphiniums grow tall, and don`t take up a lot of area, and you can grow "shorter" plants in front.
This planning is not just a "shove it in the ground" job, is it..
My front border is 40' x 4' and the side is 20' x 4' ,the 4' parts are just in progress, as I am widening them to allow me to plant my helebores, snowdrops and the vast amount of fuchsiasi have bought in the front of the beds.

 

My rule of thumb is to plant too close together, then if stuff thrives, I move stuff about

 

Thanks for you input ,I must admit I do like both ideas.But just in case I am going to put some more annual seeds in propagator to fill in the gaps if need be.

 

They do need enough room to develop....although sometimes a bit close brings a nice show.