location please.. big city name ... growth potential varies according to such ...

and how about a pic ... im wondering if their failure.. is simply your expectation of instant gratification???

i might suggest.. that all spirea are dense.. given the 5 or 10 years it might take.. for them to grow to that height in fill in ... but i surely wouldnt be expecting that in the first couple years after planting.. unless you bought large dense plants to begin with.. at which point.. i suppose you wouldnt be asking ...

ken

I'm in south central
Kansas (zone 6b), but don't obsess over the climate zone. The Froebelli Spireas have been in the same
location for over five years. They get
morning sun and afternoon shade, and I've already explained the climate. The climate isn't the issue. I really think it is the lack of full sun
that is the issue. The nursery that sold
them to me warned me that they may become leggy in partial shade. I understand what you are saying about giving
them more time, but I don't think time is going to cause them to fill out along
the vertical stems. In my three photos
you can see how they have leafy ground cover and leafy tops but long bear
middle stems. Those bare stems just keep
getting longer and even the leafy parts get long wiry stems with only leaves at
the tips of them. In my estimation,
those are all signs of not enough sun.

What I need to know, as my
original question states, are there any cultivars of smaller spirea that will
grow dense (without becoming leggy) in part shade? If not, then I may go with my new plan of
some dwarf panicle hydrangeas.

Have you never pruned them? Formal 'box shaped' hedges need to be pruned from an early age to get dense growth. I don't think there is any cultivar which would naturally grow dense when planted in a close row. I'm pretty sure any cultivar would need pruning.

Yes, I've pruned them every year, but they keep growing all leggy.

Leggy to me says having bare bases. But yours look like they are shooting up top growth and IME that is fairly typical of most of the larger Spiraea. The smaller ones won’t get to three or four feet IME.

A neighbor one block away had spireas, and he trims his into a box-like hedge. They are never leggy, wiry, scraggly, or whatever you want to call it. Why won't my spireas grow that way? His are in full sun btw.

Can you add a photo of the neighbor’s spiraeas so we see your goal? Are you certain that his are Spiraea? I honestly haven’t seen a Spiraea I would want for a 3’-4’ clipped hedge. Box-shaped says to me formal looking, and Spiraea growth patterns don’t seem particularly formal to me. Mine grow like a fountain, arching up and outward, and that is fairly typical IME. What is your goal for the hedge? Do you want flowers or a formal green wall? Would you consider a plant that isn’t a Spiraea? Would you consider an evergreen such as boxwood or yew, two plants commonly used for hedges?

I'll get that photo. I'm pretty sure it's spirea. It's very low maintenance. He never waters it or fertilizes it. He just sheers them once in March or April. They also get clusters of little, white spirea-like flowers on them in May or June.

Check out Snow Storm Spirea (not to be mixed up with Snowmound). It grows in a dense mound. Dense for a spirea, not boxwood dense. But if a Spirea is what you want, I could see it being trimmed into a hedge.

However, it might be bigger than you'd like. Mine has grown to about 4' high and probably 5' - 6' around. But I haven't tried to manage its growth like you might if you want it in more of a hedge form. I trim it once after flowering in June and it stays tidy for the rest of the year.
It does get a few good hours of afternoon sun, dappled after that.

Here the flowers are fading, but you can see it's pretty dense compared to other Spireas.

Here are those pictures. I also took a close up of the foliage. This particular hedge is approximately 5' tall. Maybe it's not a spirea, but the leaves look very familiar to other spirea leaves as do the flowers when they are in bloom.

Thanks for the photo of the hedge. I agree with floral’s ID and my preference would also be to grow this unclipped as I like plants with a fountain shape such as some spiraeas, forthythia, and ninebark/Physocarpus to have that graceful arching form.

IME when I was a kid with a hedge of bridal veil Spiraea in the yard that was in high shade much of the day with only a bit of sun, this is not a plant that will grow densely in part shade, so I don’t think it is a good choice for what you want in your situation. Ours was always fairly sparse regardless of pruning or not.

I asked several questions above about goals and alternatives that might help you choose an alternative plant. Here are a few more:

Is this a spot you want to be attractive in winter? (Evergreen or berries or bright twigs)

Would you be happy with a plant with a dense mounding form that grows to 3’-4’ rather than a box-shaped hedge?

Is the fine texture of the Spiraea part of the appeal or would a larger-leafed plant work well?

Thanks for the information and ideas. I will probably move my spireas to a different location and put something else in their place. I'm not sure what. I for sure don't want a 5' tall hedge. So, now I'm thinking, do I even want a box shaped hedge at all? I don't mind a plant that can grow 4-5' tall and wide. I do have Catmint in front of the spireas, so perhaps something behind them that would pair well with the Catmint. Any ideas? Maybe something that is floral or a texture that would be a good backdrop for Catmint. Keep in mind the afternoon shade, hot dry Summers and cold dry Winters and that continuous wind.

If you don’t care about winter appeal, check out Caryopteris divaricata Snow Fairy. It has variegated leaves and is herbaceous. Not sure how it would do in morning only sun since mine gets sun from 10 am on.

See how Hydrangea paniculata cultivars do in your area as you drive around. Are the blooms white or pink or have they just turned brown? Some smaller cultivars to look at include Little Quickfire and Little Lime. They are far more tolerant of dry conditions than other Hydrangeas, and mine haven’t ever been watered since year two (or three if there was a severe drought). They have done fine with 6 weeks of no rain.

Yews are shade tolerant evergreens and prune well into boxy hedges. They are deer favorites and so wouldn’t work with deer around.

There are relatively small red-twigged dogwoods. Most have ornamental flower panicles and berries, some have nice yellow autumn foliage, and several have red or even gold twigs in winter. Again, check how they do in your area since my area is very different, but they do well in southern WI where it is also quite windy IME.

I will see if I come up with other ideas.

I do have panicle hydrangeas in my yard. I have both Little Line and Limelight. Limelight would get too big for the front of my house, and I really don't want more Little Limes. I am considering Silver Dollar panicle hydrangeas. Do you have any experience with them? I think they are a fairly new cultivar.

I am also considering Ruby Slippers Oakleaf hydrangeas. Both oakleaf hydrangeas and panicle hydrangeas do well in my area. Both types get white leaves that turn brown in with the first frost.

Sorry, I meant white blooms. lol

My area is too cold so I have no real experience with any oak leaf hydrangea, and I also have no experience with Silver Dollar panicled Hydrangea. But here is the Hydrangea forum on Houzz, and you could ask for experience there.

https://www.houzz.com/discussions/hydrangeas