Cup plant (Silphium perfoliatum) adds a lot of wildlife value to the garden. The plant's leaf bases form cups which provide water to birds and insects, butterflies regularly visit the flowers and birds feed on their fall seeds. Cup plant is easy to grow from seed and although it is mostly native to Southern Ontario, it does well in zones 3-8.
Wet and cold stratification required. Mix seeds with moist substrate (vermiculite, perlite or moss) and place in a plastic bag and refrigerate for 6-8 weeks. Sow seed at 1/8 inch depth. Do not let seedling dry out while it is establishing.
Sow directly outdoors in late fall to overwinter.