Tree that blooms in July?

Hi Victoria...I suspect that your magnolias are soulangeanas! We're all still waiting for a pink-flowered grandiflora. The breeders have produced some yellows, though
I wouldn't have dared suggest Albizzia unless it was to be sited in the SW, although I did grow it without problems on clay in the Midlands. It didn't flower profusely, though. That may be because it was seed-raised? Top of my wish-list at the moment is A.j. 'Summer Chocolate'..

 

When I was in my twenties I knew a girl who's parents had planted a (flowering) Magnolia [big one, probably M. soulangeana] on her 1st birthday - in the middle of the circle in their front drive. Looked absolutely stupendous on her 21st birthday

I agree it looks awesome and also disagree it is a lot of work. My mother had a few "weeping" roses - basically something grafted onto a standard and an umbrella shaped wire frame for support / training, and they just did their thing from there. The variety of Rose, to work well grafted onto (or grafted and grown as) a standard, will be the trick. Best to ask a specialist Rose nursery what they suggest.

Personally I think that David Austen roses are over priced; lots of good specialist Rose nurseries about. Save your money although if you only want the one plant then buy what you find that ticks all the boxes, from wherever you find it

Tulip tree (Liriodendron tulipifera) might flower at the right time? Not pink, and may not be flowering "low down"

Worth looking in the garden centre at the specific time to see what they are flogging - they'll have everything that is flower to tempt folk

We had a rose-up-a-tree at our previous house. I took this photo on 22-June ... no repeat flowering once its over, but did look spectacular. Watch out that it will be earlier in the West Country.

 

Just like to add my Albizzia flowers in August so might be a bit late.

Surely not in July C1?

Catalpa, might be an option, although more cream coloured than pink from a distance. Flowers back end of July.

 

Nice looking leaf on that tree too [Aurea version available] ... same with Tulip tree ... and Paulownia & Judas Tree (which I discounted earlier as they flower earlier). But that misses the "something special on/around your daughter's birthday" point)

 

A bit of a long shot, but could be worth a try. Chitalpa.
A hybrid between Catalpa and Chilopsis, not easy to get hold of though and needs a hot spot.

http://www.bluebellnursery.com/catalogue/trees/Chitalpa/C/6633960