Hollyhocks (Alcea rosea) are a traditional cottage garden flower that are easy to grow and enjoy. Once these plants begin flowering, maintain the growing conditions you used to nurture them to the flowering stage. Deadheading spent flowers, the cutting away of the old flower spike, allows the plant to sprout additional flower spikes and repeat a flowering display. Repeat the deadheading on each plant's flower spikes to coax repeat blooming up until a killing frost.
Maintain good growing conditions for the hollyhocks once they've reached flowering age. Make sure the soil remains moist and stake plants that are tall and may topple in gusty winds.
Cut off the flower spike once all the flowers are spent. Blossoms open from the lowermost reaches of the spike and progress upwards as long as the stem continues to lengthen. At some point, however, the tip reaches its maximum height and the flowers wane even at the tip. Cut the spike near the base of the plant, 10 to 24 inches above the ground and 1/2 inch above a leaf on the stem.
Apply a liquid fertilizer to the hollyhock after cutting off the spent flower spike. Follow label directions for dosage and timing of feedings on the fertilizer product.
Allow side shoots and buds to develop and grow from the base of the stem you cut in Step 2. These shoots will become secondary, smaller flower spikes.