Several answers come to mind.
For instance, "Lots, but fewer than last time, with lots more to go".
Or, "One gardener's mistake is another gardener's taste".

My taste is to planting perennials close and getting continuous and changing colour from early spring to late fall; obviously, labour intensive, not so cheap and a bit of a juggling act.

In our location, asters (especially New England asters) and fall monkshood are my favourite fall plants. The best hardy mum, I have, is 'Mei Kyo', but it blooms infuriatingly late.

By fall, the garden has risen from the low plants of spring to the tall plants of fall, with a large amount of cutting back and progressively more staking.

For me, tall mauve, purple and pink garden New England asters (vigorous No Names bought twenty years ago) provide the height (with Arend's monkshood), 'Purple Dome' is the shortie, and there'd always be lots of magenta 'Alma Poetschke' in between.

Got to also give credit, though, to the phlox still in bloom, and some other real stalwarts, also still in bloom, like Geranium 'Rozanne' and various perennials with variegated leaves.

This works for me (usually!).
And there's always next year, if it doesn't.

I should have divided the tall sedums, Autumn Joy, Matrona & the variegated one.

ATekk wrote: The numerous pinching worked great on my shorter asters like Woods Blue, but the taller species are now so engulfed in blooms that they are too top heavy and flop not aesthetically.

But I thought one consequence of pinching was to reduce the height of the plant so at the time of bloom there is less 'flop'.

My husband forgot to remove the 25 asparagus crowns from the cart before a seed purchase. So, we accidentally bought 25 asparagus crowns. We ended up putting them towards the back of a large bed near new shrubs and trees that will take a long time to fill in. Turns out, asparagus isn't a good backdrop for other things. Too light green and weedy looking. But we're stuck with it for now, because we don't have another place for 25 asparagus crowns. Hopefully it will at least be delicious!

This happened last fall, but I'm thinking about it now that the leaves are starting to color.

I let my neighbor put about a dozen bags of leaves out by the curb for trash pickup. They were even nicely mulched by the mower. I could have really used them around the garden and in the compost but felt silly taking his trash. This year I'll have to man up and just ask for them.

I'm continuing to let a campanula spread throughout one of my beds. I don't know how I'm ever going to get all the little roots out and I kind of look forward to the big patches of purple. But I did get rid of the three other patches that sprang up this summer.

heh heh... 25 crowns of asparagus :)

Campanula mentioned above.

Several of the garden ones are spreaders and also very difficult to eliminate from a perennial bed.

In my experience, Campanula punctata (Spotted) is the worst. The related C. takesimana (Korean) is supposed to not be so invasive, but I'm suspicious of that one too.

Yes those campanula can be like unwanted house guests ;). But as you probably know there are several which do play nice. The two that I have that stay where they are put are "Summertime Blues" and just this past year I planted "Freya". What I like about SB is that it can do well in much less than full sun and "Freya" is very compact but floriferous.

Just made one last week -

A few months ago, I decided to attempt to plant under our Norway Maple as it take a full corner of my small lot. I put in a few things, lost a few small things, but realized that bigger plants usually held their own. The hydrangeas and big hostas even flowered. So last week I came across a Brunnera and it was large and, although expensive, I figured if everything else is doing okay, I will stick this in there and see how it does.

Well, this morning I had the pleasure of digging up the now leafless Brunerra and transplanting it. Now I will have to baby it in an attempt to get it to come back in the spring.

Lesson learned - do not put anything expensive that you really want to keep around under a maple

If anything, Campanula takesimana is even MORE RUNNING than punctata. But the most persistent with coming back with me was C. glomerata.

aha, I was waiting for your glomerata sniff, W. I don't care for it either. Have noticed you are rather (ahem) ambivalent over quite a few campanulas and they generally get you SHOUTING a bit.

Campanula, I LIKE campanulas , but NOT the running ones. They ANNOY me. I have latifolia, lactiflora, trachelium, carpatica, Kent Belle and Purple Sensation. I have plans to buy Sarastro. I even have one from Iran, but I never remember its name(bought from Monksilver Nursery in England, but they do not seem to sell abroad anymore? They always had something special.)

wieslaw, how about giving "Freya" a try? It was bred almost in your backyard by renowned plant man Arie Blom. I had 3 in my garden this past spring and all did well in this their first season (sorry no pictures).

Now I don't want to scare anyone but here is a picture from this past June of my clustered bellfower (Campanula glomerata) just starting to open:

Here is a link that might be useful: Freya

Only "ANNOY", wieslaw.

I've used quite a few different campanulas too.
But digging out delicate soft white branching root systems (from the same plant, over several years!) drives me straight up the wall.

I may have disliked goutweed (bishop's weed) more, but I knew enough to never plant that one anywhere near a perennial bed.

My biggest mistake was in not cracking the whip hard enough at my sweetie. While he was out tilling, installing, fixing, digging, inspecting, and otherwise taking care of our friends, neighbors and extended family, my flower beds fell upon some neglect in the areas that I could not reach. Most notably, the Rudbeckia has taken over a major part of their beds and the tall sedums are flopping due to not being pinched back to control height.
Next year, I vow, will be different. But I say that every year. I am married to the neighborhood handyman, and I wouldn't have it any other way. He takes very good care of me!

ATekk wrote: The numerous pinching worked great on my shorter asters like Woods Blue, but the taller species are now so engulfed in blooms that they are too top heavy and flop not aesthetically.

rouge21 wrote: But I thought one consequence of pinching was to reduce the height of the plant so at the time of bloom there is less 'flop'.

I found that the size was most noticeable on the shorter varieties. Aggressive pinching worked wonders because it the mounds very compact and flopping or opening up in the middle is non-existent. The larger varieties however only slightly decreased height and because the branching went so crazy up top, the pure weight of it could just not be held up.

What Ive always been told is that with the tall asters, you have to pinch or actually cut back several times summer. Cut plants in half or even two thirds in early June, repeat in early July and if you are in a long growing season, repeat in early August. It was hard for me to be that brutal several times a summer, but you end up with a great dome of color in the end.

I knew last spring that I should have divided sedum Autumn Joy but let it go for another summer. Next spring I promise myself I WILL do it.

I did not severely cut back my Butterfly Bushes in the spring. We have had what I would call "mild" winters the last couple of years and my Buddleia no longer die back to the ground. Before I know it, they are almost completely leafed out, with just a few tips that have died back. I find myself then just cutting off the dead ends, leaving the bulk of the bushes full sized to start off the growing season. They end up to be HUGE by the end of summer.

Next year, I will definitely trim them all down to about 10 inches in the spring.

Also, I, or the soil it was planted in, managed to kill a two year old Agastache Tutti Fruiti. I loved it so much, as did the bees and hummers, and I am so upset to have lost it. We have clay soil and although it was in amended soil, maybe the lack of drainage down below was too much for it. Maybe I'll try another Agastache from seed and see how it goes.

Linda

Among others I continue to make these mistakes:

- if there is space, I fill in with a plant (even though I do know that other plants nearby will grow to fill in that space)

- for a plant that really catches my fancy I purchase too many of them (see older thread)

Here is a link that might be useful: Perennials you love *too* much

Mistake, Rouge!

Bet, with most of us, that's the norm.
And we can't all be wrong. Can we?

Same "mistake" I always make - I forget to water. Or, rather - I just don't water. I HATE to water plants, so I tend not to [shrug]. I will water the potted annuals if I notice they're wilting or if I remember it's been a few days and I *should* water them. Come mid-August or so - forget it already.

Got a sprinkler system installed this past spring - money VERY WELL SPENT. The beds finally aren't a crispy mess by August and I don't even have to think about watering - except the potted plants...see above.

I haven't gotten around to planting some plants I purchased in August, and I do consider that a "mistake", although really it is a time issue rather than a mistake. I'm debating planting tomorrow, because this season everything is early, all the way from spring onward, we've even had FROST already in my area. I realize frost won't harm hardy perennials and shrubs, but I'm thinking perhaps the hard freezes and temps cold enough to affect soil temp aren't far off this year - normally I'll plant all through October, and I have planted into November in years past with great sucess, but this year does give me pause. Then again, I should just DO IT already because I do have the time tomorrow; otherwise, it just won't get done because of my schedule then I have haul everything in the garage for the winter. BAH!

as usual, I sow far too many seeds, make far too many divisions and cuttings and end up running myself ragged trying to keep them all alive in various locations around the house, garden, allotment and general neighbourhood. Every year, I swear I will be more circumspect and sometimes I am - I no longer attempt 20 different tomato or potatoe varieties (or remember which has an 'e' at the end), nor do I feel compelled to sow every seed in the packet but still....seeds are my weakness (so cheap, so varied) and I succumb to catalogue descriptions with the gullibility of an infant. The garden becomes a no-go zone with every surface littered with pots of seedlings, all floorspace used up (a complete nightmare in the dark) and any attempt at order or labelling doomed to failure. It does make me generous with passalongs and presents though.