Posted: 22/01/2014 at 15:00
Where in Portugal? The Atlantic coast can get mist even in summer, lowering the temperature to jumper and jacket wearing territory till it lifts. It can also get close to freezing in winter in much of Portugal. She should see what thrives in local parks and gardens and use that.
Allium, Oleander, Wallflower etc should do fine.
Vines like Mandevilla, Bougainvillea should provide almost evergreen flowers.