Minnekota, good choice, very hardy, 3' tall in 10 years, good color.

Connecticut Yankee, very hardy, 4' tall in 10 years, good color.

Purpureum Elegans, good choice, very hardy, 5' tall in 10 years.

Hellikki, very hardy, 5' tall in 10 years.

Catawbiense Boursault, good plant but 6' tall in 10 years.

English Roseum, more of a lilac-rose pink and 6' tall in 10 years.

Roseum Elegans, more of a lavender and 6' tall in 10 years.

Thanks Rhodyman - I'm going to stick with the Purpureum Elegans.

How much of a footprint should I maintain for a Purpureum when selecting location?

I'm thinking of planting 2.5' to 3' from the house foundation but there is a short 6" retaining wall about 4' to 4.5' away from the house. If it grows to 5' tall, does that mean I need a 5' x 5' footprint?

Purprueum Elegans is described as: Robust, upright, well-branched shrub. Typically after 10 years it will be 5' to 6' tall and 4' to 5' wide. Eventually it will grow over 8' tall and 6' wide. You may want to consider a smaller plant unless you want fast results.

OK, thanks. Can rhodos be trimmed to maintain a certain size? I'd like to keep to under 5' tall/wide if possible.

I would like to add the following:
Rh. Purple Splendour (hybrid) - darkest purple I know
Rh. cuneatum (specie) - close to violet than purple
Rh. Ana Kruschke (hybrid) - more violet than purple

Rh. Purple splendour:
The darkest purple I have is "Purple Splendour." It blooms in late May in my area (the Greater Seattle). As a matter of fact, it is in bloom right now. It tolerates shade well. Mine is under Acer Palmatum facing west.

I have the following description in my garden notebook:

Purple Splendour. 4ft height and 3ft wide. - 10°F. Mid-may. Ruffled, rich deep purple blooms blotched back purple. Informal growth to 4 to 5 ft.. Hardy and easy to grow. Sun or shade. The darkest purple I've ever seen. This is a Rhod. ponticum hybrid.

Rh. cuneatum:
Another Rhody I could recommend for purple color is a Rhododendron Specie called "R. cuneatum." This is much lighter purple and blooms early (late April). Below is in my garden notebook:

R. cuneatum.
April - May. From china. It could grow to 5 feet tall in 20 years. R. cuneatum was discovered by Forrest in October 1910 on the eastern flank of the Lichiang Range, western Yunnan. The plant grows on rocky slopes, on limestone cliffs, amongst rocks and scrub at elevations of 2,745 - 4,270 m (9,000, 14,000 ft). The species was first introduced by Forrest in 19?3 (No. 10423). In cultivation it is a broadly upright spreading or somewhat compact shrub up to 6 feet height with thick branchlets, although in its native home it reaches 12 ft in height. The plant is very hardy and fairly fast-growing. It is free-flowering, and provides a fine display with its deep rose, purple flowers in cluster of three to six Epithet. Wedge-shaped. Hardiness 3.

Ana Kruschke:
7ft height/8ft wide -10 F. Mid-May. light reddish purple flowers are 3 inches wide and are borne in cone-shaped trusses. This attractive compact plant tolerates sun and heat well. The dark green leaves are 5 inches long, and the foliage is dense.

I have Ana Kruschke that is about 18 years old. It is about 7 feet tall and 8 feed wide. It is hardy, drought tolerant once established and blooms spectacularly in a sunny location.

R. Purple Splendor will not grow in Zone 5. Everyone tries it, but no one can keep it alive.

R. cuneatum is tender and not even close to Zone 5.

R. Anna Kruschke would probably be OK and likes sunny locations, but is way over 4 to 5 feet tall.

Rhododendrons can be trimmed, but many varieties will keep a nice compact shape and size naturally. This is a much better alternative. My recommendations are:
Minnekota and Connecticut Yankee which naturally have small size and good compact shape. The taller plants that are pruned frequently get sparse on the bottom unless they have lots of light.

Thanks jhjohn and rhodyman.

I will try to find Connecticut Yankee at my local nurseries. If I can't find it, I may consider going with the Purpureum and either trimming or living with the larger size. It will see a good 5 hours of morning sun everyday (at least when it is sunny out)(7am-noon).

I, too, am looking for a purple rhod - as black purple as I can get. No reddish/pinkish or mauveish purple. Someone mentioned that 'Purple Splendour' is the darkest purple they have seen.
As you all know, photos on the 'net vary greatly. If you have or know well 'Purple Splendour' can you please verify for me the accuracy of this pic?

If PS really does look like either of these image links, I think I would be happy but some of the other images in Google Image look vastly different. I desire the blackest purple I can get.

I've included one link below and here is another:

Many thanks from this anal gardener who loves to have a color co-ordinated garden. :-)

Holly

Here is a link that might be useful: {{gwi:391337}}

Here's a few more for Z5 in the true, deep purple range:
Jonathan Shaw
Edith Bosley
Polarnacht
Olin O.Dobbs

All of these are good, compact growers which will remain relatively small compared to purpureum which is really more lavender than purple.

holly bc: Since you live in the heart of North America's best rhododendron growing region, you have many choices. Purple Splendor is an old standby purple, but there are newer varieties (many of them with Purple Splendor in their genes) which have deeper, richer flowers and better growth habits. 'Black Widow' is a new variety with really dark flowers. 'Polarnacht' and 'Rasputin' from Germany are newer deep purple varieties. 'Olin O. Dobbs' is an older excellent dark purple with thick waxy flowers which intensify the color.

Rhododendron 'Polarnacht'

{{gwi:391338}}
Rhododendron 'Old Port'

{{gwi:391339}}

I find R. 'Polarnacht' one shade darker. The buds are almost black. I also find it more freeflowering and the flowers are larger. 'Polarnacht' has survived more than three months with hard frost (down to -20C) and heavy snowfalls this winter.

How about Purple Passion, there are quite a few of them in my area zone 5 in MA. They are very hardy and aren't supposed to get any taller than 5 feet. The color is lovely.

Linda

lindama: Have you really seen Purple Passions in Z5 that look anything but dead after their first winter? All the ones I and many other people have seen lost 2/3rds of their leaves and while not technically dead, might as well be.

It is possible that a large number of PP's came on the market from flawed tissue culture (the big box stores were full of them last year) or that two different clones exist, but I sure wouldn't recommend this variety to anyone. It has a pleasant flower, but it's not the deep purple originally asked about, either.

If you grow Purple Splendor it must have excelent drainage. Joe

I planted a PP 2-3 years ago from a local nursery in MA - so far so good and it looks very healthy.