“sometime in mid-fall, just before your first expected frost, mound the plants with shredded leaves, compost, or straw to protect the crowns. Do not cut them back at this time. In the early part of spring, remove the dead foliage by cutting them just above soil level. Apply an all-purpose granular fertilizer, preferably 10–10-10, around the crowns to help promote new growth. Assuming the plants are at least three years old, you should then get excellent growth and a good harvest next summer.” Source