Because it grows slowly and is somewhat fussy about soil, therefore people who think arbor vitae and Stella D'Ora are the summit of All Growing Things don't like it or recommend it.

It is somewhat tricky to grow, even in the most suitable locations. Needs a cool, rich, acidic and moisture retentive soil, best in partial shade and can be prone to winter cold damage, drought stress and leaf blights. Even in my nearly perfect climate for rhodies and other Ericaceae, kalmias are hard to grow well. But a good number of cultivars are on offer at local nurseries - 'Elf', 'Minuet', 'Sarah', 'Keepsake', 'Ostbo Red', etc.

We have Kalmia by the zillions here in suburban Philly, most of them put in as foundation plantings in the postwar years. At my old house, built in 1948, we had a huge one that reached up to the roof (it was a 2-story house). They are lovely and carefree plants here.

This is very coincidental- just this morning I was considering a post wondering why Kalmia were not more popular. I love them and think the flowers are truly fascinating and unique.

I am growing Tiddlywinks, Olympic Fire, Nipmuck, Sarah, and will be adding more as time goes on.

Yes, mine are slow, but I do not find them fussy at all- I guess my conditions just work somehow.

This is Tiddlywinks-

I've been at it again, just got back from what may be called a local "heath bald". This is an area where soil experiences heavy drainage and is highly acidic. Few if any trees are found in a heath bald. Soil here is light and sandy, not much organic matter. When you walk across it you sink in. Imagine in the height of a drought how dry this soil is.

Not the best pic but you get the idea. Large ML in the back surrounded by thousands of Gaylussacia, Vaccinium, & Lyonia, also an occasional Amelanchier. The foliage is fire engine red in October. Wouldn't you think that this area is teaming with mycorrhizae?

Pieris and Rhodies grow like weeds for me but I've killed three Kalmia...

Took this pic 2 weeks ago at prince William forest park in va, which is loaded with them. They do have a pretty loose habit which is why I doubt I'd put it in my yard, but it does look interesting up close:

thanks mattp321, nice clean foliage on your ML.

I'm fascinated how plants with minute seed can regenerate, it seems the developing seedlings have an affinity for moss.

^^That baby rock plant with it's single flower is a prime illustration of how life finds a way. That is just too precious.

I think I have found the spot that GG mentions for a suitable location. This is my kalmia yesterday. It has always been one of those spectacular June bloomers. Blooms profusely every other year. This is an "on" year. I really like how the buds are much darker. Between the buds and the flowers this shrub has color for at least a month. This gets a little more sun than where one would expect to plant a kalmia, but before planting years ago I had read that they can be open/loose habit in shade and more compact in a bit more sun. I figured in NH it could perhaps take a little more sun.

"Even in my nearly perfect climate for rhodies and other Ericaceae, kalmias are hard to grow well."

But it all depends. Kalmias grow wild here in coastal Cecil County and I've found them incredibly easy when planted out compared to say, Rhododendron 'Nancy Evans'. Which would be easy for you in the PNW but is ungrowable here w/o antifungal treatment or grafting.

The mountain laurel king is without dispute Dr. Richard Jaynes. This youtube is about his work.

Thyme2dig, what is the name of your ML?

Thyme: that is an awesome plant!

Sam, I planted it about 14 years ago, and I think I remember it being 'Olympic Fire', but not 100% sure. I checked online and some sites picture it as the color of mine, and other sites show it as quite red. I'd be crushed if I ever lost this shrub. So far it has come through some pretty rough winters unscathed. I think there was only one year where it looked pretty awful in spring, but bounced right back.