I have 'My Mary' in my garden and a couple of observations/comments.

I don't believe that this hybrid will grow to 8'. 4' at best (at least here in the Northeast).

It is NOT stolniferous. If you have to prune, do so selectively (ever so judiciously) if you received it as you described with the subsequent growth habit being confined to the top to produce a leggy specimen. Personally, I feel the plant will outgrow your current displeasure with the way it is growing. It takes time to get established and comfortable in it's new environment.

I've never done a blessed thing with mine. In fact a neighbor (young girl) used to use my yard as a 'cut through' and trampled my plant years back, breaking off the top 1/2 of the plant. That was the only pruning that was ever performed on the plant. It's now nice and well formed, but in all honesty it doesn't look any different than when I recieved it (thank you Betty Cummins).

My suggestion? If you desire to give it to your daughter/d.i.l. don't do anything with it. Let it grow. Allow it to re establish itself in it's new home, and hold off on any pruning (if any) for a couple of years. You may be surprised at the results.

" Let it grow. Allow it to re establish itself in it's new home, and hold off on any pruning (if any) for a couple of years. You may be surprised at the results. "

Ditto.

Few years ago I receive mature, but very leggy 'Mount St.Helen' azalea on a basis 'if you'll not take it it will go to compost pile'.
Based on its original location I have a thought that legginess developed due to too much shade and planted mine in well watered Western exposure. I didn't prune a single branch.
In a second year after planting I noticed a lot of small side shoots from previously bare main stems. This past season many of them become a branches and most of them have a flower buds for the next year bloom.
I think, in a couple of years it will be a nice full shrub.

According to Greer: (deciduous azalea) ÂMy Mary  (Beasley) A beautiful plant, rounded in shape and crowned in late April with light brilliant yellow 2½" flowers. ItÂs a fragrant offspring of ÂNacooche x R. austrinum, a stoloniferous azalea with stems that grow horizontally.

According to Rare Find Nursery, it grows to 3-4' tall and 3-4' wide. Hardy to -20F. In George Beasley's own words: "Our finest seedling from our controlled crosses is a lovely yellow. It has more than I had hoped forÂbeauty, charm, good tough leaves, good plant form, hardiness and strong pleasing fragrance. Only one name seemed adequate for this fine plant. 'My Mary' was the choice. Normally a husband should be able to expect some small credit for naming an azalea for his wife, but as always, I blew it. In the plant description I stated that the plant grows as broad as tall!"

Thanks for all the response postings. I hope that in zone 8 the 'My Mary' will grow beyond 4 feet tall, but if that does not happen, I still am very happy to find an azalea which blooms yellow with flowers that seem to look more like rhododendron flowers.

Now I would like to find some azaleas which bloom purple and others which bloom white, but do not ever grow taller than 3 feet. Even better would be ones which never grow taller than 2 feet tall.

I planted a small "My Mary" in 1998, obtained by mail order. It grew very slowly until 2005, when it suddenly took off and added 50% to its height in that one year. It has grown at a normal rate since then and now is about seven feet tall. It is still growing, and I will not be surprised if it reaches eight feet in another two or three years. It has a narrow habit, much narrower than tall. It blooms well with a somewhat spicy odor detectable fifteen feet away.