When should asparagus ferns be cut back?
Written by
Paul Reynolds
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Trimming asparagus ferns ultimately sustains crown health and initiates the new season's harvest. Asparagus ferns, located above the ground, serve as solar panels that create and store energy for the plant in the crown. Cutting too early will weaken the necessary energy reserves of the crown. On the other extreme, cutting too late risks the diseases that reside in ferns, which overwinter in plants. Use this seasonal schedule for good plant development and growth.
Spring Growth Phase
- Allow all spears to develop into full ferns
- Never cut green ferns during this period
- Support tall ferns with stakes in windy areas
- Ferns convert sunlight into crown energy reserves
Summer Maintenance
- Remove only damaged or diseased fronds
- Keep ferns healthy for maximum photosynthesis
- Water adequately during summer heat
- Monitor for asparagus beetle infestations
Fall Preparation
- Cut yellowed fronds at soil level
- Leave green ferns until frost arrives
- Apply balanced fertilizer in early September
- Build winter mulch around crown bases
Your climate will determine the timing of winter cutback. Wait for the first hard frost that blackens ferns. This signals the plant that it is time to go dormant. Cut the ferns back to an inch above soil level. Remove all debris to avoid disease overwintering. After the cutback, immediately mulch for protection.
Bad cutting can damage the crown. Cutting green ferns in the summer will starve the plants. Leaving dead ferns can lead to fungal diseases. Use clean, sharp tools. Sterilize blades with alcohol in between plants. These practices demonstrate professional infection control and limit the transfer of disease.
There are special notes for non-frost climates as well; if frost is less likely, then cut ferns in very late December. Alternatively, you can minimize even that if the yellowing of the fern is attributed to overwatering. You can use lighter mulching in warmer climates; however, this is a sound adjustment to avoid crown rot.
Effective fern maintenance enhances future production. Ferns with productive energy reserves produce thicker spears. The long-term objectives are best achieved through disease prevention and planning for your plants' future. Your thoughtfulness in timing will lead to certainty of harvests for decades. This simple, habitual process ensures the minimum loss and maximum sustainability of your investment's savings.
Read the full article: How to Grow Asparagus from Crowns Successfully
