If old flower stalks are allowed to stand ... Bearded, beardless, and Siberian iris do not need fertilizer. Reblooming types of iris, however, do benefit from fertilizer. Fertilize repeat bloomers ...
To best support rebloom, soil fertility must be adequate, and adding fertilizer after June bloom will help promote late-summer flower bud initiation. Vigorous young iris clumps are more likely to ...
We grow several different types of Iris at Oudolf Garden Detroit,' says Meredith Simpson, horticulturist and leading grounds ...