Trailing Petunias are guaranteed to make an amazing display every year. As long as you feed them regularly you can have a display from June until October. You can start off in spring with baby starter plants, and as these grow take cuttings. One baby plant will easily make 3-5 more plants.
This year as well as the usual baskets, we lined our wall with grow bags, and planted Petunias and lobelia in. The grow bags work really well, to ease watering cut the bottom off small water bottle and stick into a small hole in the grow bags ( 2 per bag). Even in the recent hot weather you can get away without having to water every day. As the season progresses you really do need to give them a liquid feed at least once per week to keep the flowers coming. It’s also worth dead-heading if you can reach them. The varieties we grew this year were Surfina “Snow”, Blue Vein, Purple Vein, Hot Pink, Crazy Pink, and the double Joanna. Without a doubt Hot Pink is the best performing one for us, holds up well after rain.
To take cuttings I simply pinch off about 1″ of plant just below a leaf pair, pull off the bottom leaves and any flower buds. I then put them into a small pot with already watered compost, into an unheated propogator ( seed tray, plastic lid). It normally takes 2-3 weeks for them to root. Please note that I did see on one plant I bought that propogation was not allowed, so of course only propogate plants you’re allowed to.
The below images links to suppliers sites, although it is getting late in the season to get plants now, you can never plan ahead too early 😉