Okay, mine is the Red Twig Dogwood shrub. At our last home, the developer of the subdivision put two of them, along with two Spireas, a Burning Bush and a token tree in front of EVERY single house. These were small yards, and the shrubs grew like weeds. Apparently they didn't realize that this shrubs natural height was 8' 10', which would completely block the front window of the house, if not severely pruned, sometimes twice in a summer. Every time I had to prune them, the skin on my arms would break out in hives. I know it wasn't the shrubs fault. It was just a case of the wrong plant in the wrong location, but I'm afraid I still hold a grudge against those shrubs.

Bonnie

I bought a larger gauge shotgun and several boxes of shells just for Horsetail (Equisetum hyemale).......:)

Daylilies. I have never seen one that made me like it. Oh sure, the individual flower is pretty enough sometimes and it lasts a whole day! Or two. The plant is ugly both in and out of bloom. That orange one used in corporate lots in particular is sad, but even the better ones still cannot compete in my eye with anything,

I thought about making a similar thread a few months ago but stopped- don't you think this thread might step on a few toes?

Certain sedum. They remind me of broccoli.

Nah, Fledgeling. I love sedums and broccoli, but it doesn't bother me a bit if Redsox doesn't : )

Bonnie

I agree with mxk - barberry in any form I cannot stand.

To add a few others to the list that I absolutely loathe are: English Ivy, Euonymus, Vinca minor. They all creep, crawl, climb (except the vinca) and damage plants & structues and they are impossible to keep cleaned out except with a high powered leaf blower and need constant pruning and spraying (in the case of the euonymus for scale). I wish these could be banned from the trade for their invasivesness but probably all the landscapers would rebel.

Yucky, I mean Yucca

Striped petunias

Coral-orangey impatiens

Dusty Miller

Leyland cypress- Overused as screen ,ugly(IMO) and prone to disease, in my area.
Bradford Pear - Another overused tree. Almost never pruned properly. Subject to severe wind damage.
Juniper - Every Office, business, apartment, condo, etc. complex, MUST have Junipers in their landscape! Lazy man's lamdscape. Designers with no imagination! Had some once, about 45 years ago, became infested with red spiders, had to eradicate all of them. Still get the creeps when I see it.
Three mistakes I made, when I planted;
Iris japonica, Japanese Running Iris. Very appropriate and descriptive common name. Spreads by long stolons and will cover the earth in a lifetime, if not kept in check!
Disporum sessile 'Varigatum' Spreads by rhizomes and seeds all over. Dig up dozens, pull them up, cut them off and they return with a vengeance!
Japanese Beech Fern - Very vigorous and spreads rapidly. Already invading my lawn from nearby beds. Difficult to eradicate, because each minuscule bit of root left behind, will form a new plant, seemingly overnight!
New York Fern - These I did not plant, knew how invasive they were. Came as hitchhikers, with other natives. Same problem eradicating, as Japanese Beech Fern, above.
EOR
Rb

Norway Maple...invasive, messy and a ton of leaves to rake in the fall.

Euonymous...prone to scale, for me anyways. I've ripped all of mine out.

Bradford Pear...beautiful in the spring, but overused, like Rb said.

Arborvitae that is brown and neglected. Very rarely see nice green healthy specimens.

Raggedy, mis-shapen Forsythia. They are blooming right now, and they are EVERYWHERE! Aside from a brief period of bloom, these are ugly shrubs. They are almost always pruned terribly, if they're pruned. Otherwise, they grow into a mis-shapen mess. People don't usually give them the space and full sun they need to grow into a graceful, arching clump.

I don't hate Hostas or Heuchera, but don't understand people's obsession with them. Most Hostas look the same to me. Most Heucheras look like little clumps of leaf lettuce. Masses of them are just plain boring.

There are lots of invasives that are easy to hate - Oriental Bittersweet, Norway maple, Buckthorn, etc. Ditto on the Barberry - whoever thought that this prickly, stubby, invasive shrub was interesting?

And I have a neighbor who could make ANY plant ugly. He prunes his Lilacs into a rectangle with a flat top using electric hedge clippers - never thins or weeds them out, and they never bloom. When I pointed out that they wouldn't bloom if he pruned them like, he said "I like them like that". (He is basically a nice neighbor, but what???)

Oh, I could probably go on...hehe

Oh my, let's see ...

It's easy to hate the invasives, the plants that once took over your garden and you've never forgiven them for it. Perhaps too easy. Instead, I'll name some plants for which I have a little more irrational dislike.

Celosia. Weird little artificial-looking blooms. Blech.

Cannas. I don't know why, but I really don't like the look of cannas, especially red ones. They literally make me recoil when I see them in a garden.

Bergenia. Again, for no reason I can identify.

Purple Palace heuchera, which looks like a bucket of dried blood. Not in any way "purple." (I do love many cultivars of heuchera, but not this one)

Anything that looks "weedy" (achillea comes to mind first)

Anything with magenta-colored blooms. I don't want plants screaming at me.

Geez, that was easier than I thought! :)

BABY'S BREATH!

The self seeding so-and-so! And If I want my bed to stink like Baby Powder, I'll shake some on the ground.

Burdock!!!!!

While I don't hate hostas, they don't do much for me either. I don't think they are that great looking unless you have deep shade and can't plant much else. I definitely don't understand anyone who loves them!

What I really don't like though is maroon plants. Somebody wants to call them burgundy, but they are really just muddy brownish red and ugly. Barberrys, plums, japanese maples, whatever. I do like true burgundys, deep red and purples but not maroon.

I"m another celosia hater. They look unnatural in most northern gardens

Yucca and canna. And of course poison ivy.

We're not counting weeds, now are we? But if we are I'll vote for the ground ivy, that has cute little purple blooms around now. A little bit came a-hitching along with a plant and now my entire lawn is infested. It does not respond to weed killer, either.

Those spirea with yellow/orange/chartruse new growth which looks lovely, until they flower with those ridiculous pink flowers.

Me, I like barberries, most types anyway, my Darwin's barberry has candy-orange flowers at the moment, next to a candy-pink red current. I have the most irresistable urge to plant bright blue flowered pulmonarias under them and create a totally inelegant blast of color.

I guess I'm not that discriminating. I don't hate anything, except maybe junipers that have been given poodle pom pom haircuts. I can even tolerate the occasional squat little marigold if planted skillfully. I will say that I haven't properly warmed up to 'Jack Frost' brunnera. It's not that it isn't a pretty enough plant, but I like the green leaves so much better--and I think the silvery pulmonarias have better silver than 'Jack Frost.'

Oh, my. As is true for others, first are the invasives: elephant ears, equisetum, bamboo, etc. I, too, vote thumbs down on Bradford Pears and Leyland Cypress. When we lived in New Orleans twenty years ago, I heard an older woman gardener say that "True New Orleanians don't plant palm trees!" I confess that I am of her age now and her opinion too. Add to the list Photinia (Redtip) which is always full of mildew and seems to inevitably clash with anything else planted near it. Then there are marigolds, that red annual salvia that so many adore (sorry), and almost anything that has been hybridized to the point that it reaches out, grabs you by the throat, and socks you in the eye when you walk by.

All this being said, there is a good reason that there is both chocolate and vanilla. The truth is I really like some of the plants on the above lists. So, there you go. :)

Yes, Hostas are kind of like weeds to me. I only use them when nothing else will grow there. And the Stella d'Oro or however you spell it daylily. Anything I see all over Walmart's landscaping; I get tired of seeing that.

Chocolate lysamachia, chocolate lysamachia, did I mention chocolate lysamachia. Spreads EVERYWHERE by underground runners.

I agree about the daylillies, and I have avoided them like the plague in my gardens. The other day a neighbor (whom I barely know) came over and presented me with a huge clump of them. He was so proud of them and all I could do was smile, thank him, and try to act thankful. But you know what I was thinking in my mind. When I asked him the color of the bloom, of course he said yellow, and he said he ordered them from Spring Hill a few years ago. I knew I was looking down the barrel of Stella.

There is no way I can just huck them, because he will come over and expect to see them somewhere. And they need full sun, which is at a premium in my gardens. Damnit! What am I going to do with them? I refuse to put them in the front yard (which is where most of the full sun is). The worst thing is that I don't like yellow blooms in general (except maybe a very pale lemony type color, and I have nothing on my entire property that is yellow.

Until now. I guess I can just cut off the blooms and grow the foliage, but the foliage is no party either!

Hate marigolds. Hate plantain lilies (especially as every second person calles them "plantation" liles and I have to wrestle myself to the ground to avoid correcting them.) Hate gladiola.
Love love love daylilies, there is a quartermile long hill along a well-traveled road near me that is planted by the owner with such a variety of daylilies that they bloom almost all summer. I go out of my way to pass it. My bridesmaids carried the apricot ones.

I'm OK with barberries (have a couple Crimson Pygmies for a shot of purply goodness among my silver foliage) and I am a big juniper fan: Wichita Blue, Grey Owl, the creeping kinds, Sea Green. I like their toughness, adaptability, growth habits, and especially the silvery-blue shadings. But I can appreciate how you can get sick of almost anything if it's overused or badly pruned/cared for--I hate Burning Bush for that reason: the "Builder's Special" shrub! I hate zinnias. They're too candy-bright and look like a child's drawing of a flower, to me--very fake. Also hate marigolds. Don't care for tropicals, either. And my least fave: any shrub or plant with yellow foliage. Looks sick and chlorotic to me.