I've been back in school, working with children of key workers at Heald Place doing a variety of gardening and outdoor learning.
One thing that went well was to dry and press flowers and then to use them to make a card to take home. We picked the flowers and put them between a folded piece of kitchen roll. Then we left them under a heavy book for a week in the classroom.
When we got them out they had dried really well. The flatter, thinner flowers worked best. We then used PVA to glue them to a card and children wrote messages to someone at home.