1989: Perfume Puff Ponies
RED ROSES
Yellow unicorn pony with pink mane and tail, aqua and pink spritzer symbol . Scented.
Although the whole set was sold in the UK, distribution must have been a touch wonky, because I never ever saw any of them in stores in my part of the country, and finding them at carboot sales round here has also always been something of a nightmare.
Therefore I can only conclude that some areas had them more liberally than others.
Red Roses has the dubious honour of being the only mainstream yellow adult unicorn that Hasbro produced throughout the whole My Little Pony line. She was also the only unicorn from the Perfume Puff set, sold with that pale pink hair that fades easily in the sun. (therefore any found with white hair are not variations but sundamaged).
Like with others in her set, Red Roses' magic was to do with flowers of the scented variety and making them appear thanks to her unicorn magic :)