"Round" is the part that makes it difficult, if it needs to be evergreen. Not evergreen, I would say youpon. Not round, I would say daylilies or maybe amaryllis. What about wax myrtle? It's evergreen and can be sheared, and it smells nice when you brush past it. When it gets too big, replace it.

You might consider a non-shrub and a non-meatball shape--I like evergreen ferns in containers that are relatively small, such as the dimensions you gave.

Holly fern and Autumn fern are evergreen in your zone and can get 18-24" tall, give a nice arching look, and like shade. While evergreen, they also benefit from pruning out blemished fronds, which can be done here and there rather than on some tight timeline, and they rejuvenate well. If and when they seem to get too big for the pot, you can pull them out, divide them and re-pot and have more for your yard.

I have to say my first thought was ferns too, and depending on how closely you look at them and whether you have snow cover in winter, you might even choose some of the deciduous varieties which are stunning up close (OK, I like ferns).

As for shrubs, if you want to treat this plant like boxwood then you might as well use boxwood. There are over 200 varieties and some grow very slowly so I'm sure you can find something that will be OK in the pots for at least 5 years - but then anything will need repotting for soil replenishment anyway around that time. You may have to go to a specialty supplier, probably on-line.

If you can dispense with round and want a small and interesting evergreen shrub, I might suggest a holly that has more interesting leaves and structure - I love Ilex (I think it's crenata) 'Mariesii' or there's an even smaller one or two called, I think, 'Green Pagoda' and I can't remember the other - I could check later. They have neat shapes and grow slowly. But from a distance they might just look blobby, and then you might as well have your globe.

To some extent the choice depends on from where you will view these planters. If only from a distance, then shape is your issue and leaves don't matter. Or maybe your look is starkly formal, which I have to admit I really admire in many settings. I'd just never have the self-discipline to forego the more interesting plants, but the truth is that the more interesting the plants, the more informal the look.

There are some tiny yews if you go to specialized suppliers, but I'm not sure they lend themselves to pruning. A plant you want to shear, as I say, might as well have no intrinsic personality as all its personality will be pruned into it and will come from its role in the overall design. Kind of like a chorus girl vs. a prima ballerina, and a show made up of prima ballerinas would be a bit of a mess!

Short answer: find a slow-growing boxwood, and do your pruning thing!

KarinL

Having the plant in question remain in a rounded form seems to be the limiting factor. A 13" diameter container will accomodate small shrubs for several seasons but eventually anything will need to be removed, root pruned and the soil refreshed before replanting or alternatively, the plant replaced entirely (and perhaps transitioned into the permanent landscape).

For something a bit distinct from the ubiquitous green boxwood, you could try a variegated form. Dwarf pieris would also be suitable - the cultivar 'Little Heath' has variegated foliage and can be pruned into a tightly rounded shape after bloom season. New growth will also feature salmony-red tones.

You could also increase your choices if you wanted to go with a more columnar approach. Ilex crenata 'Sky Pencil' or Cupressus macrocarpa 'Wilma Goldcrest' (commonly referred to as lemon cypress) would work nicely. Also rushes, like Juncus 'Elk's Blue'. Columnar plants may offer a better opportunity to underplant with annuals for some seasonal color.

Hi Cadence,

I saw a wonderful article in a landscaping mag that talked about the urn being treated as an entire landscaping project. By utilizing different sizes, colors and textures in each urn. Have a tall accent plant and surround it with medium sized and on the outer edge plants that would spill over the side. The illustration were very striking in that the urns were very finished and rustic looking and all looked great. GL and aloha.

I think the common verbiage hinted at above is "thriller, spiller and filler" when it comes to planting in containers.
A 10x13" urn isn't large and I would think even a small evergreen shrub would exhaust the potting medium pretty quickly. Is the boxwood hedge going to be formal and/or meatballed and the urns a continuation of the formal layout?

You might be limiting yourself as to the possibilities since annual or perennial plantings in containers can be formal - and maybe in your zone can be kept going year round in one fashion or another. Just more work than a sheared shrub.

I don't do a lot of container plantings, but have kept Colorado Blue and Norway spruce volunteers alive for years in gallon pots until I could find just the right place to incorporate them into the yard. So it obviously can be done.

But for my one classic urn viewed looking up the long slope of my side yard and from several other points, I never get tired of a "spike" behind the biggest true red geranium I can find along with mounding white petunias, and some sort of trailing ivy or sweet potato vine to spill out. You likely have a more vivid imagination.

I know it's not round, but it has beautiful foliage, does ok in a shady area, and smells heavenly during early spring is Daphne Odora. We have some next to the front door of my office and it just stopped being so fragrant you had to pause and smell every time you walked in or out.

Wow! So many ideas, I feel like a kid in a candy store. lol
Thank you all so very much. I have to admit that I have no idea what some of these plants look like so I will have to do a little Google researching. Then I'll go and check out a few nurseries on the weekend. I'm going to print out all these fabulous suggestions.

Hmmm never thought of ferns. I like the idea of placing them later on in my backyard near the cedar trees. It get's shady over there and I'm planning on putting a water feature and patio there next year.

I forgot to mention that I have a row of rhododendrons going down one side of my lawn. They have huge red trusses (Jean Montague)So, I want to be careful with too much color. I will be putting the boxwood around the other 3 sides (L-Shape) The urns are placed on either side of my bay window. There is a raised flower bed directly below the window and the urns are placed on either side of that. I also have a small Japanese Maple(burgundy lace)in the centre of the lawn. I definitely wants something dark green foliage. I think it would also set off my 'moss green' shutters. My house color is called 'antique cream' I am going for a formal look if possible.

If I have to remove the plant in 5 years, I really don't care. It might be time for a change by then anyway. lol.

Doing some looking sounds good. What I think you want to do is to get some idea of what you'd like to look at day in and day out. It won't be such a problem to replace in a few years--it's not like you're digging up a tree--unless you invest in something really super pricey. If it's slow-growing, you need to pick a size that's large enough to have some presence now yet still have some years to go. If you like something faster growing, it needs to be prunable or dispensable and replaceable with its junior cousin or with whatever your new fancy in a couple of years. If you grow to love it and want to keep it and it responds to root pruning, then root pruning a 1-foot root ball isn't such a lot of work.

I think you have room to "make a mistake" and not get too worried about it.