I suspect the trend to shorter/smaller plants is related to smaller properties whose owners tend to scale down everything in the landscape. The smaller properties have been cited by a lot of garden centres that closed as a key factor in the decline of their business - i.e. small properties = less space for a garden = fewer plants sold (and I’d guess smaller plants are more likely to be seen as ‘in scale’ to the smaller property, plus the garden centre might be able to sell more of the smaller plants to cover a given space - meaning more $ if the price doesn’t vary much between the larger and smaller variety...) That’s my theory...:-)

^^ Yea...McMansions on spitball-sized lots...sigh...

I'd agree that the industry pattern is the dwarfing of everything. House lots are smaller and most people want as little work, like pruning, as possible.

Look to the native perennials for tall and stately. Things like Joe Pye, Ironweed, Culver's Root. A number of asters will grow taller. Angelica, Aralia cordata and A. racemosa, Persicaria polymorpha and Filipendula are all large stately plants. Large herbaceous perennials will of course be a little harder to find in a nursery.

Growing from seed may be the easiest remedy as more variety is available.

Look at some native plants - I have several that get over six feet, and more in the 4 - 6 foot range.

I second Yardvaark's seed recommendation.

I agree with you, mxk3. I grow from seed, and even then some taller varieties are harder to find. Standard tall goatsbeard, does that exist anymore? Only seeds I can get are a dwarf variety. What about those astilbes that used to be so tall? Gone. Just the short varieties now at nurseries and seeds purveyors. But, still a greater selection of tall plants using seeds, in my opinion.

(I feel so fancy using a word like "purveyors.")

I’ve complained about the same thing. It’s when I started to notice that taller monarda were harder to find unless shopping online, and every nursery was selling small mounded ridiculous looking bee balm. In a way, I selfishly enjoy it just because many of the perennials that inspire the most, “What is that flower?!” comments from neighbors are the tall huge perennials that you just don’t see as much anymore. As others have said, many of them are native cultivars and many have fallen out of favor. But trends change and there are two competing trends now. More millennials are gardening now. (My generation.) And many millennials tend to rent and or live in cities. So that has spurred nurseries to sell smaller compact plants. Who wants one 6’x4’ plant in their 2x4 flower bed when they can cram in a dozen tiny guys. Also marketing. Most of the large perennials look dull and downright terrible when small enough to be sold in pots. Unless you really know your plants, you‘d pass them by for the small already flowering plants. Most gardeners or the dreaded phrase, “yardeners“ choose their plants by what they see blooming at the nurseries. Only then do they mayyybe read up on it online. Nurseries commonly treat seedlings and nursery potted perennials with growth inhibitors to keep them small as long as possible. A counter trend is also in full swing though. That is the trend toward natives, native cultivars, xeric, and prairie style gardens. This style focuses on pollinators, water-wise plants, closer planted and larger plants to minimize seas of mulch, and emulates natural American prairies. oddly, this trend started in Europe and they’re responsible for many cultivars of American natives. What was weedy to us was exotic to them. Many nurseries online now supply these huge plants and I’m seeing more and more in brick and mortar nurseries.

Some of my favorite large perennials: Maximilian sunflower, lemon queen perennial sunflower, herbstone rudbeckia, giant rudbeckia, veronicatrum fascination, joe pye weeds, cardinal flower, larger echinacea (not the mini fluorescent orange ones), and swamp milkweed.