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Pruning Asparagus

A question came in to Ask Gardenerd this week:

Could
you please help me understand how to trim my 4’ tall asparagus patch
that was planted in the fall? Does it need to turn completely brown? How
low do I trim it?

Great question, and the answer can be confusing, because there are two schools of thought on the matter.  Many gardeners, including those at Peaceful Valley Farm and Garden Supply (here’s their video), recommend cutting asparagus back in the late fall and mulching with straw to protect the plants from frost.  This can help prevent the crowns from rotting from fungi that develop on the plant over winter.  Some say to cut back the fronds at soil level, other say to cut them about 1 inch above the soil.

On the flip side of the coin, there are gardeners and farmers who leave their foliage until spring.  Much like bulbs, those fronds are collecting nutrients for next years production.  There are farmers who also claim that the existing foliage will tent snowfall (if you have that) and insulate the plant from frost damage.  My own personal pruning preferences reside on this side of the coin.

asparagusinlatefall
One of our asparagus beds in late fall.  Partially brown, not yet ready to cut back

There’s a reason why I leave the foliage until spring: habitat.

About 3 years ago, when I first planted asparagus, I noticed in late summer and early fall that ladybugs would “move in” to the asparagus patch to mate and lay their young.  The benefits were obvious.  Ladybug larvae eat about 400 aphids in a couple weeks, meaning my garden would be practically aphid-free by the end of their visit.

ladybugonasparagus
Just one of hundreds of lady beetles that makes our asparagus patch home for the winter

ladybugsonasparagus
Behind the dead asparagus fronds is a renegade tomato plant. 

This year our lady beetles have more to munch on.  Our renegade tomato plant volunteer from summer is still producing, but is beginning to be covered with aphids.  The lady beetles are taking swift action, enjoying themselves immensely.

So in the spring, I will cut down my asparagus foliage, and layer about 1 inch of compost in each bed.  That will give them the signal that it’s time to start producing.  Over winter, I still water occasionally, but much less often.  In snowy conditions you wouldn’t do this, of course.

I hope this helps. Thanks for your questions – keep writing in.

Hey gardenerds, what do you do with your asparagus? Share your experiences with us here.

This Post Has 60 Comments

  1. Tara

    Happy Spring 2021! your article was very helpful 🙂 I have a question I planted asparagus, but being a novice gardener I put in a spot that cast more shade during the summer months on my other beds. Can I trim some of the height to help the other veg- maybe a foot but leave the rest so the asparagus can build up its energy for themselves?

    Thanks!! 🙂
    Tara

    1. Christy

      Good question, Tara. Since the leaves are what stores energy for next year’s asparagus, I’m always hesitant to advise any pruning. You can tie them up together to eliminate some of the shade, perhaps, but I wouldn’t cut them back.

  2. Wendy Zwecker

    I think I made a huge mistake…I cut back my ferns too soon. I planted my asparagus thus Spring and they looked amazing. They were starting to turn color and there were some berries and I cut them back as I was working on other beds. Did I destroy all the work to get this bed established?? I was going to mulch with hay today…

    1. Christy

      Wendy, you’re not alone. You’re not the only one who has cut down the biomass early. At least they were starting to turn color. Like bulbs, asparagus takes nutrients in from the fronds and stores them for next year’s spears. You may see a decrease in production next year, but boost the soil in spring and see what happens. Wait until they turn brown before cutting them down next year and they should recover. Fingers crossed!

  3. Diane Trucks

    This is my 2nd year growing asparagus. There was so many bugs and worms on all the ferns and even the stalks. So I cut all of it off, a lot of it was dying. The stalks are about 3 feet high. Did I just kill my crop. I’m hoping it comes back. It’s May 31. Can I do anything for them?

    1. Christy

      They use those fronds to store energy for next year, so you may experience a setback. That said, it’s still early so you may see continuous growth through summer to replace those fronds. Leave them in place if you do and consider dispatching a troop of lady bugs instead. They hang out an eat the aphids and other critters on the fronds.

  4. Fatima Choukmaev

    Please, I need some information on my case. My asparagus plant is one year old. It looks very healthy, my problem though is
    that I live in Brazil and the beautiful fern won’t die because of our mild winter.
    My question is: Can I cut off this ‘ green’ fern to encourage the spears to come out?
    Or will this trimming hurt the roots?
    Thanks in advance

    1. Christy

      Fatima, the asparagus fern should at least turn brown or lose color to some degree even if it doesn’t become dry and crisp. When it does, you can cut it down. The plant uses the fronds to gather energy for next year’s crop, so if you cut it down too early, production will go down.

  5. Deborra S McCauley

    my asparagus garden has been over ran by weeds. I fear I will hurt the roots if I try to dig out the weeds. What is best to do? Location, Winston Salem, NC

    1. Christy

      Good question, Deborra. If the weeds are superficial you’ll have no risk of damaging your asparagus crowns (the roots are very deep in soils). However if they are runner weeds that go down a foot or so, you might want to wait until the plants go dormant in fall to dig the weeds out. If they are damaged during dormancy, they will recover in spring with new root growth.

    2. Karie

      Question, after you cut the asparagus, do you ever remove the dried out stump that is left behind?

      1. Christy

        Yep, I just did that the other day. At some point they will become soft at the base and you can lift those out pretty easily. If they don’t come out easily I leave them there. You can cut them down closer to the soil level so they don’t visually distract you from the beauty of your garden.

  6. Jean

    I moved into house in this month. Cleared out garden area, not realizing there was asparagus. Will it it come back next year?? Thank you.

    1. Christy

      Since asparagus is much like a bulb in that the foliage helps gather nutrients for next year’s crop, you may see a drop in production next year, but they should still come back if tended properly. If any other foliage appears this year, don’t remove it. Let it turn brown at the end of the season and don’t harvest any of the asparagus to allow it to recover.

  7. Milly Traut

    How do I prepare my spring garden with one year old asparagus coming up. I understand I should not harvest them for another 3-4 yrs? How do I care for them in the meantime?

    1. Christy

      HI Milly, the rule of thumb with new asparagus is to not harvest in the first year, harvest only a few spears in the second year, and a regular harvest the third year on. To care for asparagus this year, cut back any brown/dead foliage and add a layer of compost and mix in a little organic fertilizer for. According to Mother Earth News there is work to be done before you put your bed to rest over winter: “In early winter, after several hard freezes have damaged your asparagus fronds, cut them off and compost them to interrupt the life cycles of insects and diseases. Fertilize the bed with a 1-inch layer of rich, weed-free compost or manure topped with 3 inches of straw, rotted sawdust or another weed-free mulch. Clean spears will push up through the mulch in spring. Fertilize your asparagus again in early summer after you’ve stopped harvesting spears. You can top-dress with a balanced organic fertilizer, or scatter another inch of rich, weed-free compost over the decomposing mulch.”

      I hope that helps.

  8. Ronnie

    We live in northern Minnesota and our asparagus ferns are quite dense. I’m inclined to agree with the idea of wintering over the ferns for protection against the extreme temps. I have side-mulched with pine needles this fall and plan to add more in the Spring when I cut back the ferns. What do you think?

    1. Christy

      Sounds like a good plan to me, Ronnie.

  9. Barb Abela

    Can I trim back the green ferns that are handing over everything without hurting the plants. I am getting asparagus but not many. What to do to increase the yield.
    Thank you for your help. Barb

    1. Christy

      Hi Barb, think of asparagus as you would a bulb. The foliage is doing an important job of collecting energy for next year’s production. So allow the ferns to turn brown before you cut them down. You’ll have a higher yield next year if you do.

  10. Bonnie Beresford

    My asparagus bed is three years old this year and the foliage is like a jungle. I’d love it if ladybugs moved in, but instead I get asparagus beetles. I have to spray every few days to kill them off, but they come back and the foliage is so thick it takes a lot of spray to cover it. Last fall and this spring I spread a commercial kind of nematode around the bed, and I do think they suppressed the beetles for a while, but only until late August. I really REALLY want to cut down the foliage to get rid of the beetles! Any advice?

    1. Christy

      Bonnie, if you can wait until your frost approaches to cut back the foliage, that would be best. I highly recommend putting down worm castings when you see sucking insect infestations. Worm castings have chitinase, an enzyme that dissolves the exoskeletons of soft bodied sucking insects. The plants take it up and helps them fend off the beetles. You may want to apply another round of nematodes too. The nematodes work, but they only catch the bugs during certain parts of their lifecycle. So reapplication is a good idea if you want to get them all. Also, the natural predator of the Asparagus beetle is the Tetrastichus asparagi wasp. I don’t see any available for sale, but perhaps if you contact your local University they may have a source. Also, import ladybugs and lacewings. They eat the larvae.

  11. Brenda

    My asparagus patch is about 7 years old. I need to cut back the green ferns now due to some construction being done on the building right beside the patch. Is there a way to do this to preserve my patch? I appreciate any suggestions. Thank you!

    1. Christy

      HI Brenda, if you have to cut them back, I guess you don’t have a choice. If there is a way to just bend them down to keep them out of the way, that would be a better option. Those fronds are storing energy for next year’s harvest so you may see a reduction in production next year if you have no other option. They should bounce back if there is a set back. Keep us posted.

      1. Brenda

        Thanks for the advice and idea. I think I’ll try laying plywood over the bent stalks. Hopefully, that will minimize damage.

        1. Christy

          That will work, just try to take the plywood off regularly to allow for sun exposure when work isn’t being done in that area.

  12. Debbie

    I am harvesting spears out of a 3 year old bed. There are many thin spears that have already ferned out. My harvest time has about 3 more weeks. Should these early ferns be cut back until harvesting us done?

    1. Christy

      I usually leave the ferns because, like bulbs, they gather and store energy for next year’s harvest. If you cut them down early you lose that energy. Some people leave them over winter for habitat, and cut down in spring. Others cut down in fall. Check your water to make sure they are getting what they need.

  13. Ronda

    It’s mid-May and my asparagus stalks are brown. What is the cause of this and what can I do about it? Thanks for your help.

    1. Christy

      That does seem a bit early. The stalks dry down at the end of the season, usually in fall. I’d check your irrigation to see if they are getting enough water (or too much). Did you harvest any spears early in the season? How many years have your plants been established?

      1. Ronda

        Thanks, Christy, for your help. I really appreciate it. My husband gave lots of TLC to the asparagus bed. He passed away about a year ago and I’m doing my best to keep it going. I’m not the gardener!
        I haven’t harvested any spears yet, but there are some green ones coming up. I haven’t done any watering because we have had plenty of rain and April snowfalls (I live in Iowa). I’m hoping with some sunshine things will look better. This bed has been producing for about five years or so.

        1. Christy

          Hi Ronda, it’s hard to keep after a garden, especially if you aren’t the gardener. I hope the garden brings you some peace, however. Keep us posted on the asparagus as the season moves forward.

        2. JR

          do you mean the ferns are dry from last year? pull them up, then when you are done harvesting this year the plants will keep growing and produce new ferns that will be dry next year!

  14. Linda Taylor

    Some of my asparagus has already turned green and is very tall; 3 to 4 feet. Some produced edible stalks. Its late March. Do I cut the tall ones now or do I have to wait till November? Thank you!

    1. Christy

      Leave the fronds until fall. The plant uses those to store energy for next year’s production.

  15. Nancy Mills

    I live in Baja California Sur, México. I have a great asparagus bed. It’s 4 years old this year. It NEVER freezes here, so only random fronds turn brown. Therefore, I have no idea when to cut them back. One guy at the seed store said November. Any other thoughts? Thanks

    1. Christy

      Hi Nancy, it’s your choice. You can cut the brown fronds down in fall (November) or you can leave them until early spring and cut them back then. My asparagus was a habitat for ladybugs so I always left it over winter for them. If you don’t see activity in your plant bed then you can cut it back if you don’t want to look at it over winter.

  16. Mark Hoy Jr.

    Very , very helpful. Thanks a million

  17. Linda Morgan

    This is the second year for my asparagus and I did not harvest. I’d like to cut them back now though because they all got bent over in a storm, they didn’t break. I can’t seem to get them to stay upright now even with support. Any reason not to cut them?

    1. Christy

      Yes, there is a reason not to cut them. Asparagus is like a flower bulb in the way that it stores up energy for the next year. Those fronds are gathering nutrients and energy for next year’s fruiting. Leave them there until they turn brown, then you can cut them down if you wish. I leave mine over winter because the lady bugs use it as habitat, then I cut it down in early spring. Either way, if you cut them while still green you will greatly reduce their potential for next year.

  18. Loann

    We live in the country of Panama…in our new home there is a really nice garden with some very tall asparagus fronds – please, tell me what to do and I will do it!

    1. Christy

      HI Loann,

      The first thing to do is make sure it is the edible kind of asparagus, rather than asparagus fern. Asparagus fern is an invasive plant that will take over your yard if you let it. I’d get that out of there if it’s not edible. If you’ve verified that you have edible asparagus, let the fronds grow until fall, and you can cut them down when they turn brown and dry out. Some people leave them through winter and cut them in early spring because they can provide habitat for lady bugs and other beneficial insects. Cut the fronds down to the soil level in spring (or winter, really) and then amend the bed in early spring for new growth. That’s about it.

  19. Donald Adams

    You should pick the red seeds and not let them sprout the following season. More plants will crowd out what you have already planted and current plants will not produce as much.

  20. Laurie

    I have a newly matured asparagus bed. This year, I have been distracted with home projects and rainy weather, so wasn’t cutting spears as often as necessary. Some of the stalks are large in diameter as well as tall. They are still producing minimally but since it’s so early in the season, should I cut back the stalks now and maybe get more produce? Would that hurt the plants, or maybe benefit them?

    Thanks.

    1. Christy

      Given the timing, it’s an odd time to cut back all the stalks. Cut away any brown stalks, but leave the green ones for now. In the fall you can cut everything down if you like.

  21. Matt Walsh

    OK, I have them cut back, but how high? Right now sprint is just right around the corner and my asparagus is about 6-9″ tall. Too high? Not high enough? We left them at about 18″ over the winter and they caught a nice amount of snow for insulation. We just cut them back a bit more in preparation for growth. Should I take them down even further?

    1. Christy

      Matt, you would cut your old asparagus fronds down to the soil level. New shoots will emerge for you to pick for dinner.

  22. Gary

    Do dear eat asparagus? I have my plants fenced in. This is my 1st year so maybe I’m overprotective. So I’m wondering if I really need the fencing? Do deer eat asparagus? Thanks.

    1. Christy

      HI Gary,

      I don’t have deer where I live, but from what I’ve read on forums where people have deer, they say that deer don’t mess with mature asparagus, but some have said they eat the young spears. Others say they never touch it. If you can fence it in, I’d go that route, just to be safe.

  23. MR. JOHNNY

    IT MAKES SINCE TO LEAVE STANDING BECAUSE OF THE LADY BUGS.ASK ANYBODY WHO GROW ROSES HOW IMPORTANT LADY BUGS ARE.THEY ARE A AWESOME INSEC,DO NOT DESTROY THERE SHELTER FOR WINTER.

  24. Anna Hill

    I wish I could send a picture of how my asparagus beds look they now have tiny red seed like balls on them very pretty. Can I save them to replant?
    Thanks

    1. Christy

      Yes, those red berries are the female plants’ seeds. You can save those. I found a nifty guide here: Good luck!

  25. Joe potter

    We are in June in Ohio with asparagus that grew past the eating stage into feathery foliage. It is three years old should we cut it to Encourage more shoots or let it go and wait for more or till next year?

    1. Christy

      With my own asparagus, I leave the overgrowth and new spears still show up. In some schools of thought, people cut down the foliage in fall before winter, but I leave mine through winter to provide habitat for lady bugs and some say it insulates against snow (we don’t have snow). Those fronds are feeding the plant for next year, so I’m inclined to say leave them. That said, if you wanted to cut a few down as an experiment to see if the cut area produces more than the un-cut area (both this year and next year), then have at it and report back your findings.

  26. Mary

    I planted my asparagus patch last spring. It is now tall and spindly and looks like it is going to seed. When and how much should I cut off? Will I be able to harvest some next Spring, as the pkg. said 3 years. Will that be considered the third year? Thank you.

    1. Christy

      Yes, it will look tall and spindly for the first year. When it first comes out of the ground it will look like the asparagus we know, but then the tip opens up and we see fronds appear. You’re on the right track to let that happen for the first 2 years. Next year, watch for spears poking through the soil and pick them young. It’s worth the wait!

  27. Frances Ford

    Thank you for the information. I left mine up but didn’t know when to cut it back. You say “spring;” how late, then, do you cut back the foliage? I too have noticed the lady beetles.

    1. Christy

      Glad you’ve got lady bugs too. I wish I could more specifically answer your question, but it really depends on your hardiness zone and frost dates. If you live in warm-winter climates like Los Angeles, you can probably cut the foliage back in February. I’d wait until later if your ground freezes over.

  28. Christy Wilhelmi

    Thanks so much for the honor, Dan.  I will write about it this week and pay it forward. 

  29. Dan R-M

    We always leave our foliage up, but mostly because there are almost always more pressing tasks to be done. I’d never thought that there might be advantages to doing it intentionally…
    In other news, I’m passing a Liebster Blog award to you. You do a fantastic job of covering a great amount of territory, and I think your blogging is wonderful!

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