We always save quite a few of our annual flower seeds to sow the following year and one of my favourite flowers that I grew in 2019 is the Malope Trifida 'Vulcan'. I bought the seeds from Higgledy Garden. They are easy to germinate and once transplanted outdoors they flower quite prolifically in full sun from July to September and are quite beautiful with their brilliant crimson petals about 7 cm across with lovely long yellowish green stems and leaves. These plants attract honeybees, bumblebees and other solitary bees. I haven't thoroughly tested their vase life yet but I'm guessing that it's about 4-5 days. Another favourite of mine, Phacelia tanacetifolia, is also very easy to grow and loves full sun. The seeds are tiny and if directly sown outdoors in spring they grow quickly into flowers in about six to eight weeks. The purple-pink 'hairy' flowers have a most delicate scent of lilac. It looks beautiful as a textural feature in a flower arrangement and the vase life is 7-10 days. The pollinators love this plant so much you can hear them en mass buzzing happily before you see them on the phacelia flower. Sow Phacelia in succession to have flowers all summer.