Lathyrus odoratus. Royal Wedding is a Spencer type sweet pea, so you can expect very showy flowers that appear later than other sweet pea types.The vines are among the tallest, growing to a full 160cm (96″) if given the proper trellis support. One of the best all white varieties, with petals that are slightly wavy with cream picotee edges. Developed in England in 1901, Royal Wedding is a little later to bloom but have a strong vigorous growth habit and long stems. Royal Wedding sweet pea seeds reliably produce flowers from June to September and prefer cool summer areas such as coastal BC. They have excellent fragrance and nice long stems for cutting.