What To Do When Rhubarb Goes To Seed

You walk out to your garden one sunny morning, ready to admire your lush, thriving rhubarb patch, and then you see it: a thick, alien-looking stalk shooting up from the center of your plant, branching out into an impressive, but alarming, flower head.

This is a sight that sends many gardeners into a panic, wondering what to do when rhubarb goes to seed. Here at Rex Garden, my own established rhubarb plants decided to do this very thing this year. *Some people think they're beautiful when flowering, and I agree when close up, but not so much when far off.

This phenomenon, known as "bolting," is often surrounded by myths and confusion. I decided that it was a fantastic idea to turn a common gardening "problem" into a learning opportunity and a source for new plants.

But don't worry. A bolting rhubarb plant isn't a disaster. It's an opportunity, not just for an article, but for you to grow and enjoy more plants or share seeds with friends.

My guide will walk you through exactly why it happens, what to do about it, and how you can turn this into a rewarding project by harvesting your rhubarb seeds.

Why Did My Rhubarb Go to Seed (Bolt)?

Bolting is simply a plant's instinct to reproduce. When a plant feels stressed or believes its life cycle is nearing an end, it diverts its energy from producing leaves (or, in rhubarb's case, delicious stalks) to producing flowers and seeds for new replacement plants.

Common triggers for rhubarb bolting include:

• Plant Maturity: Just like my plants, established and older rhubarb (3+ years) is more likely to bolt. It's a sign of a mature plant doing what nature intended.
• Heat Stress: A sudden, prolonged period of hot weather can trick the plant into thinking summer is ending and it's time to make seeds.
• Drought Stress: Not enough water can signal to the plant that conditions are tough, prompting a survival-of-the-species response.
• Plant Genetics: Some rhubarb varieties are simply more prone to bolting than others.

Debunking the Old Wives' Tale: Can I Still Eat the Rhubarb?

Let's get the biggest myth or old wives' tale out of the way immediately.

Yes, you can absolutely still eat the rhubarb from a plant that has gone to seed. I do!

The stalks do not become poisonous or inedible. The primary consequence of bolting is that the plant diverts a significant amount of energy into producing that giant flower stalk.

This means the edible leaf stalks (petioles) you harvest might be slightly thinner or a little tougher than they would have been otherwise, but they are perfectly safe to eat.

So go ahead and harvest your stalks as you normally would. The plant's energy is just being split between stalk production and seed production.

What to Do Right Now: The Two Paths

When you see that flower stalk and your rhubarb has gone to seed, you have a choice to make, depending on your goal for the plant.

Path 1: Prioritize the Parent Plant's Health

If your main goal is to ensure a strong, productive rhubarb plant for the rest of this season and for next year, you should remove the flower stalk immediately. *This is what I opted for with these plants the past few years.

• How to Remove It: Don't just snip off the top. Follow the thick, round flower stalk down to its base, where it emerges from the crown. Using a sharp, clean knife, cut it off as low as possible, ensuring you do not damage the surrounding stalks or the central crown.
• Why Remove It: By removing the entire stalk, you stop the energy drain. The plant will redirect that energy back into its root system and into producing more of the tasty leaf stalks you love.

Path 2: Harvest the Seeds for New Plants (My Project!)

This is the path I'm taking with my plants this year. If you want to experiment with growing new rhubarb from seed, you must leave the flower stalk on the plant to mature.

This is a trade-off: the parent plant will be less vigorous for the season, but you'll be rewarded with hundreds of potential new plants.

A Step-by-Step Guide to Harvesting Rhubarb Seeds

Harvesting rhubarb seeds is a simple and rewarding process. It just requires patience.

Step 1: Let the Seeds Mature on the Plant

You cannot rush this. Watch the flower head over the coming weeks. The small, greenish-white flowers will fade, and in their place, small, triangular, papery seeds will begin to form.

You'll know they're ready to harvest when the entire stalk and seed head begin to dry out, turning brown and brittle.

Step 2: Cut and Dry the Stalk

Once the seed head is brown and dry, use shears to cut the entire stalk from the plant. To complete the drying process and catch any falling seeds, you have two options:

• The Paper Bag Method: Place the entire seed head into a large paper bag and fold the top over. Store the bag in a cool, dry place like a garage or shed for a week or two.
• The Hanging Method: Hang the stalk upside down in a dry, well-ventilated area. You can place a bucket or a paper bag underneath to catch any seeds that drop.

Avoid plastic bags, as they trap moisture and can cause the seeds to mold.

Step 3: Thresh and Winnow (Separate the Seeds)

After a couple of weeks, the seeds will be completely dry and will detach easily.

• Threshing: Simply shake the stalk vigorously inside the paper bag or rub the dried seed head between your hands over a clean bucket. The seeds will break away from the chaff (the dried bits of flower and stem).
• Winnowing: You'll be left with a mix of seeds and chaff. To separate them, you can do this on a slightly breezy day. Pour the mixture from one container to another, letting the wind carry away the lighter chaff while the heavier seeds fall into the container. You can also do this indoors with a small fan on a low setting.

Step 4: Store Your Seeds

Your harvested rhubarb seeds are now ready for storage. Place them in a clearly labeled paper envelope or a small glass jar. Store them in a cool, dark, and dry place until you're ready to plant them next spring.

What to Expect from Seed-Grown Rhubarb

Growing rhubarb from seed is a fun project, but it’s important to manage expectations:

• It's a Long Game: Unlike planting a crown division, a seed-grown rhubarb plant will take at least 2-3 years before it's established enough for you to take a harvest.
• Genetic Variation: Seeds do not produce a clone of the parent. You may get plants that are very similar to the parent, or some that are quite different in terms of color, taste, and vigor. To me, this is part of the fun!

So, the next time you see a flower stalk on your rhubarb, don't panic. See it as your plant talking to you, and that you have an opportunity to strengthen your plant, plus harvest delicious stalks, and even to become a seed saver for the future of your garden. Happy gardening!