Why Are Your Asparagus Plants Falling Over? (How to Prevent)


Are you wondering why your asparagus plants are falling over?  You’re not alone – it is always annoying when a plant in your garden falls over unexpectedly.

So, why are your asparagus plants falling over?  In many cases, asparagus plants will fall over once they mature, usually in the late fall.  A frost could also kill asparagus spears for the season and cause them to fall over.  Finally, pests such as cutworms do damage that cause asparagus spears to grow crooked or fall over.

Of course, there are other things that can cause your asparagus spears to fall over.  In this article, we’ll take a closer look at these causes, and how you can prevent problems for your asparagus.  Let’s begin.

Why Are Your Asparagus Plants Falling Over?

These are a few of the most common reasons that your asparagus plants are falling over:

  • Plant maturity
  • Fall frost
  • Cutworms
  • Over harvesting
  • Environment and Culture

We’ll take a look at each of these causes in turn, starting with plant maturity.

asparagus leaning
Image courtesy of Rasbak at Wikimedia Commons: https://commons.wikimedia.org/wiki/File:Asperge_planten_Asparagus_officinalis.jpg

Plant Maturity

Plant maturity is one of the most common reasons that asparagus plants fall over.  Asparagus spears start to grow in the spring, and they continue to grow through the summer and fall until frost kills them.

Eventually, the spears start to look like “ferns” as the tops of the spears expand.  This happens when the asparagus plant “goes to seed”, or makes seeds to reproduce.

asparagus berries
As asparagus spears grow, they get taller and start to look like ferns. Some female asparagus plants will even produce red “berries”, which contains seeds.

The bushy top part of an asparagus plant (the “fern”) produces energy by photosynthesis.  This energy is then stored in the crown (buds at ground level) and roots (underground) of the plant.

The plant saves this energy and uses it to make the next year’s spears.  So there is a “lag” period of one year between when the plant absorbs energy and when it uses that energy to produce edible spears. (That is, this year’s asparagus spears come from last year’s stored energy).

When asparagus goes to seed, you might see red berries on some of the female plants.  You can learn more about red berries on asparagus plants (and what they mean) in my article here.

It is normal for an asparagus plant’s spears to grow very tall during the season.  You will often see an asparagus plant reach heights of 4 to 5 feet (1.2 to 1.5 meters).

In fact, they can get up to 7 feet (2.1 meters) tall, with a spread of 2 to 3 feet (60 to 90 centimeters) above ground!  You can learn more about the size of asparagus plants in my article here.

When asparagus plants get taller and go to seed, they become top heavy.  This makes it more likely that they will fall over due to their own weight, especially in windy conditions.

There is no need to worry if your asparagus plant falls over after reaching maturity.  In fact, it is necessary for them to grow tall with large ferns.  That way, they can store enough energy for the next year’s harvest.

In addition, falling over is a way that asparagus plants spread their seeds to create new plants.  If you still want to prevent your asparagus plants from falling over at maturity, you have two options:

  1. Cut back the foliage (ferns), but not while it is still green (more on this later)
  2. Support the plants using cages, trellises, or stakes with wire/twine (more on this later)

Fall Frost

Frost is another reason that your asparagus plants will fall over.  Asparagus spears start growing in the spring, and they continue to grow through the summer and into fall, until frost kills them.

At this point, the spears (that now look like ferns) will fall over.  Remember that asparagus plants are perennials, which means that the crown and roots will live on, even though the spears die back.

Cutworms

Cutworms are a common garden pest.  They love to feast on your plants.

cutworm
Cutworms are a common garden pest that loves to feed on plants such as asparagus.

The most annoying part about cutworms is that they only eat a little bit of each plant!  However, this small amount of damage is enough to kill your plants completely.

This is how cutworms make your asparagus plants fall over.  First, they wrap themselves around the base of an asparagus spear.

Then, they work their way around to see how soft the spear is.  If the stem is soft enough, they start chewing!

In some cases, the cutworm will chew all the way through the plant’s stem, cutting it down like a tree.  Instead of feeding on the rest of the plant, the cutworm will move on to cut down another, and another, and so on.

If you are really unlucky, you will see an entire row of plants cut down by a single cutworm in one night!  Even if a cutworm does not chew all the way through a stem, it can still damage your asparagus plant.

When this happens, your spears will grow faster on the undamaged side.  This will cause the spears to take on a crooked appearance as they grow.

Of course, this makes it more likely that they will fall over as they continue to grow taller and more top heavy during the season.  You can learn more about cutworms on asparagus in this article from Michigan State University.

Asparagus beetles are another pest that will make your spears look like they are curling or falling over.  According to the University of Minnesota, there are two species of asparagus beetles:

  • Adult common asparagus beetle – this one is bluish black with 6 whitish spots.  Their larvae (baby beetles) are gray with black heads.
  • Adult spotted asparagus beetle – this one is reddish orange with 12 black spots.  Their larvae are orange.

Asparagus beetles lay eggs on asparagus plants.  When these eggs hatch, the larvae feed on asparagus plants.  Then, the larvae grow into adults in the soil, and start the process over again.

When asparagus beetles feed on a spear, the spear turns brown and curls over.  As with cutworm damage, asparagus beetle damage makes it more likely that a spear will fall over as it grows taller.

Even worse, asparagus plants become weaker as a result of damage from these beetles.  This makes them more susceptible to diseases like Fusarium (caused by a fungus).

You can slow down asparagus beetles by picking them and their eggs off of your plants by hand.  Another option is to spray them off with water.

Clean up any debris (such as branches, leaves, and spears) around your asparagus plants.  This will leave the beetles with fewer places to hide during the winter.

Aggressive Harvesting

Harvesting too much from your asparagus plants in one year means they will have less energy to store in their roots and crown.  This is especially true if your plants are younger than 3 years.

asparagus
If you harvest too many spears from your asparagus plant this year, it won’t have enough energy left to make lots of spears next year.

When you over harvest from your asparagus plants, there are fewer spears left to grow into ferns.  With fewer ferns, the plant will have less energy to store for the next season.

As a result, you will get fewer spears the next year.  Any spears that do grow will be thin and spindly.  These thin spears are more likely to fall over as they grow taller.

To prevent this problem, leave some of the spears to grow into ferns each year.  This will allow the plant to store energy before it enters dormancy in the winter.

In general, you should harvest few spears (or none!) from your asparagus plant during the first two years of growth.  Here is an outline to give you an idea of how to harvest asparagus spears, based on the plant’s age:

  • 1st year: do not harvest anything.  Let all of the spears grow, become ferns, and store all their energy in the roots.
  • 2nd year: harvest 1 week at most.  Let most or all of the spears grow into ferns and store their energy.
  • 3rd year: harvest for 2 to 3 weeks.  After that, let any remaining spears grow and store their energy for the future.
  • 4th year and later: harvest for 6 to 8 weeks.  After that, let the rest of the spears grow and store energy.

According to the University of New Hampshire Extension, you should harvest asparagus spears when they are 6 to 8 inches (15 to 20 centimeters) tall.

Remember that the number of spears you get next year depends on how much energy the plant stores this year.  So, be patient in your harvesting so you can get more asparagus spears from stronger plants in the future!

If you give your asparagus plants proper care, you should be able to harvest for 20 years or more.  Don’t be greedy, and stick to the harvest guidelines listed above!

Environment and Culture

Maybe you are sure that your asparagus plant is not falling over due to maturity, pests, or over harvesting.  In that case, it could be a simple matter of the wrong environment for your plants.

Let’s briefly go over some of the usual suspects.

Light

Are your asparagus plants in an area where they cannot get enough light?  Although asparagus can tolerate some shade, it needs 8 hours of sunlight per day.

Without enough light, asparagus spears will grow “leggy” (tall and spindly) as they try to climb higher to reach more sunlight.  This makes it much more likely that they will fall over as they grow taller.

To avoid this, trim any branches from trees that are blocking light to your asparagus.  Also, avoid planting them in the shadow of taller plants (for example, pole beans and indeterminate tomatoes).

daylight
Avoid planting asparagus in a place where it will be too shady.

Water and Soil

Asparagus plants will not show signs of water stress.  However, they can certainly experience it!

Asparagus has a deep root system, but they do need watering.  This is especially important when they are young as they try to establish themselves.

Asparagus plants also need light, loose, well-draining soil.  Clay soil will cause problems, since it is dense and retains water.

clay soil
Clay soil drains poorly and is dense – not a good choice for growing asparagus.

If you have clay soil, add some compost to improve drainage.  You can learn more about how to improve soil drainage in my article here.

A lack of any important nutrients in your soil can also cause problems for your asparagus plants.  Make sure to use compost and fertilizer as necessary.

You can learn more about how much fertilizer to use for asparagus in this article from the University of Massachusetts Extension.

Just remember that too much of any nutrient (for example, nitrogen) can burn your plants or cause deficiencies of other nutrients.  Get a soil test if you are unsure about what to add!

You can learn more about soil testing in my article here.

Wind

If you live in an area with strong wind, your asparagus plants are more likely to fall over as they grow taller.  You cannot control the wind, but you can protect your plants against it.

One idea is to set up a wall of straw bales near your asparagus plants.  This wall will act as a windbreak during the growing season.

After the season is over, you can compost the straw and use it for your garden in the future.  You can find more ideas on how to protect your plants from wind and storms in my article here.

Diseases

Asparagus plants can fall victim to numerous diseases, such as:

  • Asparagus rust
  • Fusarium crown and root rot

Your best bet is to keep your plants healthy by allowing them to grow strong.  To do this, let them store plenty of energy in their early years (that means: don’t over harvest them!)

Make sure your plants have the proper light, water, soil, and nutrients to keep them healthy.  Proper care is one of the best ways to make your plants more resistant to disease.

If any plants do fall prey to disease, manage it by removing them.  This will prevent the spread of the disease to other plants.

Age

Remember that asparagus does not live forever.  Although you might be able to harvest for 20 years or more, the party will be over eventually.

If the asparagus plant has come to the end of its journey, replace it with another one and begin anew!

How to Prevent Asparagus Plants from Falling Over

If you want to prevent your mature asparagus plants from falling over, you have a couple of options: cut back the foliage, or support the plants.

Cut Back the Foliage

According to the Iowa State University Extension, you should not cut asparagus foliage when it is still green.  When it is green, the foliage is still sending energy to the roots and crown of the asparagus plant.

According to the Cooperative Extension, you should instead wait until the first fall frost, after which the foliage will turn yellow.

At that point, cut them down to 2 inches (5 centimeters).  As long as the plants are free from disease, you can compost the foliage for next year.

Support the Plants

You can support asparagus plants with tomato cages, trellises, or stakes and wire/twine:

  • Tomato cages – you will need a cage for each asparagus plant (not for each spear!).  As the plants grow, they can lean on the cage for support.  Since a cage goes all the way around the plant, it won’t matter which way the asparagus spears decide to lean.
  • Trellises – you have two options here.  One option is to use one small standalone trellis per plant.  The other option is to use a longer trellis (almost like a fence) to run along the length of your row of asparagus.  You might still need to use twine to tie the asparagus spears to the trellis to keep them standing.
  • Stakes – you have two options here.  One option is to use one stake per plant, and use twine to tie the asparagus to the stake as it grows.  The other option is to use two stakes, one at each end of your row of asparagus.  Then, run a wire (or twine) between the stakes, along the length of the row.  Put wires at various heights (every foot or so), on both sides of the asparagus.   This will “trap” the spears between the two wires, so that they cannot fall over.
plant cage
You can use a tomato cage to support any plants: tomatoes, peppers, and even asparagus.

Conclusion

Now you have an idea of why your asparagus plants are falling over.  You also know how to prevent it from happening if you want them to stand upright.

I hope you found this article helpful.  If so, please share it with someone who will find the information useful.

jonathon.david.madore

Hi, I'm Jonathon. I’m the gardening guy (not guru!) who is encouraging everyone to spend more time in the garden. I try to help solve common gardening problems so that you can get the best harvest every year!

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