Red Twig dogwood
Cotinus coggygria
Flowering Quince

these three.. are shrubs that sprout from below ground.. leading to multiple leaders.. and can easily. inside 5 years.. create a footprint in excess of 5 feet wide [the plant being twice as wide] .... i think that they will eventually be too big for the area ... unless you can find some named variety that is smaller ...

a nice conifer might be at the link ... i have one going on about 10 feet and barely two feet wide ... and no snow load issues ... its not flowering like you are thinking.. but it could give some vertical element w/o taking too much space ... a bit of diversity ... think outside the box you have already created ...

what about flowering almond???

ken

Here is a link that might be useful: link

Thanks Ken,

The Thuja occidentalis looks very promising! It could at least block the hole in my neighbor's boxwood hedge.

I see they are sold online and are quite affordable for less than $10 for a small 8"-14" plant. Do you know how quickly it will put on height?

I love flowering almond. Do you have it? How long does it flower for and how does it look the rest of the year?

its a plain 3 foot green shrub for most of the year.. a week or two of flowers.. depending on how hot spring is ...

the de groots... will do about a foot a year after a year of getting roots down ...

put in 3 or 4 ... in every gap of the boxwood.. and then smaller shrubs in between ...

i think there is a dwarf lilac called palibin .. and dwarf is relative in lilac ... thru rejuvenation pruning or training to tree form.. it could be kept small ... see link

ken

Here is a link that might be useful: link

If you're looking for a flowering, fragrant shrub for full sun you can't beat a lilac. Look for the cultivar called Bloomerang if you want a later summer flush of blooms, as well as the spring show. Combined with the forsythia, and a skirt of daffodils or tulips and alliums, hyacinths and/or muscari planted among the hostas or daylilies, this border could welcome spring in spectacular fashion.

Arborvitae, on the other hand, is probably the most over-used, uninteresting shrub you could plant there. Totally unnecessary as you already have the evergreen background of the boxwood hedge, which appears to only need a light trim to get rid of dead wood. The hole in the hedge is actually quite charming; if you were a big kid like me, you would see the potential. :) In any case, you could always disguise it by planting a shrub in front of it. Whatever, these are pretty big and would be expensive to replace, so capitalize on that while you can!

I'm a huge fan of dogwoods (Cornus sericea or sanguinea). Yes they are large and fast-growing, but there is a trick to keeping their winter stems bright red or yellow or orangish that effectively contains the size of the shrub. You must cut the oldest stems all the way to the ground in spring in order to get the brightest color on the stems in winter. You could try a grouping of 'Alleman's Compact' with an edging of Sedum spectabile for a reliable, all-season show.

Or maybe you would prefer a tall grass, such as Miscanthus sinensis purpurascens, or "Flame Grass" which has a smaller footprint than other Maiden grasses, or a Korean feather reed grass. Mix a few of these with a few dwarf round shrubs, such as Fothergilla gardenii or Berberis thunbergii, don't forget the sedum (I never do, lol) and you will have a border with interesting color, texture and possibly even fragrance in several seasons.

Thanks for all the advice Ken & prairiegirlz5. I have shied away from lilacs b/c they don't do as well here in the DC area as up north, although I do have a NJ Tea that I could move there.

I love sedum too and have it everywhere, but I want something big with bones too.

I am curious about the potential you see in the big hole. Please share! But remember, these are my neighbor's boxwoods, so I cannot prune or otherwise mess with them.

I like the idea of grasses a lot, and I think I will definitely incorporate them. They will also help make the border interesting in the fall.

As for the Thuja being overused, not around here! Around here it is azaleas, rhodies and more azaleas.

Arborvitae, on the other hand, is probably the most over-used, uninteresting shrub you could plant there.

===>>> agree regarding the species.. disagree on the named cultivar ...

IMHO .. she needs some vertical .... to create a boundary ... a sight line boundary ..

and she needs something that will not outgrow a 7 foot bed ...

a nice squat hedge is one thing .... but where is the vertical ...

i suppose an arbor and some clematis might be an option ...

i am not a fan of flowering trees overhanging the driveway .. though i dont have time to recheck the pic ..... and the facts ...

it will be for you to check the zone thing..

ken

I agree about the need for something vertical, Ken. I think I will get the Thuja you mentioned. I like the idea of an arbor and clematis too, but the Thuja seems the simpler option right now. And yes, this is along the driveway and there is enough of a sweep-up problem between the tulip poplar and the large oak nearby!

Here is a link that might be useful: GardenWeb

or try some clematis on the de groots when they get bigger ...

ken