The Patio Collection will provide the colours and seasonality listed below (though always subject to the prevailing weather conditions)
1 x Agapanthus Aquamarine
Deep blue flowers from mid July and into August 24” tall
3 x Lilium Casa Blanca
White flowered in July and early August 36” tall
10 x Gladiolus callianthus
White flowered (with a dark central zone) in August/September 36” tall
3 x Eucomis bicolor
Greenish white with burgundy rims, August into September flowering 18” tall
1 x Dahlia Arabian Knight
Deep crimson red, summer flowering from July through to September 30” tall
Each of the above would go happily into something like an 15” pot filled with John Innes No 2 potting compost. They could then be moved around so that whatever was at its best could be repositioned. The Gladiolus and Eucomis would be the only ones that might share such a pot reasonably successfully. If you wished to plant them all together in one container you would need something the size of a half barrel though this has the disadvantage of being unweildy to move around. Whilst you should get good flowering on everything else in the first year, it may be that the Agapanthus will be better in future years, it is just the nature of the plant that they take time to establish and perform. They would however fare well planted in such conditions (perhaps covered over with a tarpaulin in the winter when dormant and when they wouldn’t want to be so wet in December to February.
There is more cultural information against each of these items below should you want it, but there will also be individual planting instructions provided with the bulbs.