I'm sure others will speak more about the specific lavenders. But as far as the ranges, that's because there is variety in all living things including lavender. There is also variability in growing conditions of a site. Some conditions inspire wild, crazy growth. Other conditions can inspire more moderate or even meager growth. As a rule, expect something more in the middle of the range but be prepared for either end of the range.

Oh yeah, growing conditions can affect colors as well.

Variability of monitors, digital cameras, and/or printing that can radically alter the appearance of things in on-line or print catalogs. And that's without even mentioning PhotoShop! ;)

FataMorgana

Grosso is a large lavender with a moderately dark flower head and a powerful scent.
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Provence is large, but not as tall as the Grosso and has the classic lavender-blue flower color. The scent is full and very sweet.

How tall the plant gets depends on the age of the plant, and how you prune the bush.

Height can also depend on your climate - it won't get so tall if grown in a cool or very mild climate, but could get huge in a hot Mediterranean climate, like its native habitat.

As with an awful lot of herbs, they can get bigger than most people realise!

Responding to "granite" --- are you growing both Provence and Grosso in North Carolina? I was thinking of Provence, but was somewhat concerned re: height at the edge of border.

I have also seen a lot of buzz recently about a lavender called "Lady" but have no real info --- does anyone have experience with this one?

I'm growing those and more in the mountains of NC.

Lady is very, very tiny; maybe 12" tall with small (1/2" or so) very dark flower heads. It is a repeat bloomer over the course of the growing season and it is the only lavender I am aware of that will bloom in its first season. Doesn't have much of a scent.
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