red and green glass jars

Make Homemade Strawberry Rhubarb Jam

I just love rhubarb. It’s easy to grow, harvest and to make strawberry rhubarb jam. What could be better than a fruit or vegetable that is a perennial and grows easily in cold climates?

I stopped by my home garden in Southern Ontario last week to pick the last of my rhubarb. I may adore rhubarb, but can’t seem to sell the rest of my family on this wonderful vegetable. – Yes that’s right – rhubarb is a vegetable!

To make rhubarb more appealing to the boys – I make strawberry rhubarb jam. It’s easy, and they eat it up.

Rhubarb and raspberries
Rhubarb and raspberries

We have been away for most of the spring-summer – from May to July (so far!) – stopping in occasionally to check on two of our adult sons’ house minding skills (not mowing the lawn, not putting the garbage out, etc.), and to weed and divide my garden.

I attempted to divide one of my rhubarb plants early in the spring and transplant it in our new northern cottage garden. So far, rhubarb doesn’t seem to like my acidic pine-needle soil, but I will try again and get a crop growing here, once the hot weather passes.

A year or two ago, one of my boys spotted a roadside vendor with rhubarb plants for sale. He brought me home a few (while on his bicycle, yet!) and I was happy to plant them in my Southern Ontario garden.

These three once-little sprouts are now monster plants and have even occasionally produced a pretty white fluffy flower.

What kind of soil does rhubarb prefer?

Rhubarb plants are easy to grow – they just need a well drained spot, and they don’t mind a bit of sandy soil. Ideally rhubarb prefer a soil with a PH of 6.0 to 6.8. This would be moderately acidic. Rhubarb will tolerate most soils though, as long as the drainage is good and they get a bit of sunlight.

I suspect that since my northern garden has (primarily) only 100 tall foot pine trees and wild blueberries growing amongst the rocks, that what little dirt there is – would be quite acidic.

Where to plant rhubarb

Rhubarb plants have great big leaves, and SOME people think they are unattractive – so I planted them off in a corner, in my Southern Ontario plot – where they can take as much space as they like – mine are in my raspberry patch. In my Northern garden, I have also planted them near my raspberry patch – out of the way near the back of the cottage.

Rhubarb leaves dominating raspberries
Rhubarb taking over raspberries

Picking rhubarb

Rhubarb are a perennial cold-hardy plant. They generally produce stalks for picking from early May through to the first week of July. I pick mine from mid-June through the first week of July.

Pick the outermost stems – alternating between plants. We all know not to eat the toxic leaves – but the stems are fine – even the green parts. The stems of different plant varieties are more or less green than others – and they tend to be pinker closer to the soil – but you can eat the green stems.

Pull and twist stalks from the base of the stem. They should “pop” and release from the root easily. Some people (grumpy garden sorts) frown at clipping the stalk with scissors or knives. This is because the little piece of stalk that is left behind dies off and is wasted. I tend to trim this off anyway – so no worries if you want to cut. It’s hard to kill a rhubarb plant. Immediately after cutting the stalk – cut off and dispose of those big darn toxic leaves.

Each time I have visited home, I harvest some of the rhubarb and chop it up into one half inch pieces. I didn’t have time to make jam or cordial or anything else for that matter, so I froze my harvest so that I could deal with it later.

Freeze fresh rhubarb

After rhubarb is trimmed, rinsed and chopped into one half inch pieces, place the pieces on a parchment lined tray and freeze. After the rhubarb has frozen – place in sealed freezer bags or container and store right back in the freezer until they are ready to process.

It is not necessary to blanche rhubarb before freezing. You can if you prefer – depending on your recipe plans! I find rhubarb from the freezer more manageable if it is flash frozen in small pieces.

What to make with rhubarb

While it’s easy to make a stewed rhubarb with rhubarb, sugar or honey and water (and I love it!), but my boys won’t eat it at all unless it’s in strawberry-rhubarb jam – so strawberry-rhubarb jam it is! (I also make a fantastic rhubarb liqueur, with Vodka, rhubarb and sugar – which makes a wonderful “front porch spritzer” – I don’t care if the boys like it anyway).

Can you use frozen fruit in jam?

Yes! Frozen rhubarb, strawberries and raspberries can all be used in jam recipes. If you have frozen fruit at home on a tray – you will not have as much extra water – but some store-bought frozen fruit may have additional moisture added, which makes following a recipe a little trickier.

When I am harvesting from my home garden, I find it’s easier to harvest rhubarb and berries as they are available – freeze and bag them – and the make jam when I have the right quantity. Thaw the fruit first of course – and do not expect the jam to have exactly the same texture as from fresh fruit – still – I squish the fruit anyway when I process it – so I’m happy with the final product.

I am lucky enough to have frozen some organic strawberries at home as well – to go with my organic rhubarb. We brought my frozen produce bags to the cottage – so that I can keep myself busy making jam, while I wait to harvest enough blueberries to make blueberry jam.

One of my strawberry pots
One of my strawberry pots

I always make sure I have pectin on hand. (I used crystal Certo) Check to make sure you have sufficient sugar (because 5 cups is a lot), and enough canning jars. This recipe calls for 6 – 250ml jars. I rounded up 2 500ml and 2 250ml jars and then put out a few extras – just in case.

I use the Bernardin recipe for Strawberry Rhubarb Jam – leaving out the lemon rind. I love to make preserves. It’s important to always use a tried and true preserve recipe – and properly can jams and pickles to ensure that they will be safe for family and friends.

Picking rhubarb
Two rhubarb stems – freshly picked

Clean and sterilize jars and lids in boiling water. Cover the clean jars in water and boil for about 10 minutes. (I also do the rings – and leave sealing lids for later). Remove the jars and rings and set them aside. Reserve the hot water to use again to sterilize the full jars. I find it convenient to sit the jars on an enamel tray or even paper towels. This keeps everything clean and easy to tidy up later. (I spill a lot).

Strawberry Rhubarb Jam Ingredients:

3.5 cups washed, hulled and crushed strawberries

(I used frozen organic – the strawberries just need to be at a “crushable” level)

Organic strawberries
Organic strawberries

1 cup finely diced rhubarb stems (cut them into small pieces so that they cook down as well as the strawberries – you don’t want the rhubarb to have a texture like celery in your jam! – this took four or five rhubarb stems for me)

1 box crystal fruit pectin (57gm)

1/4 cup lemon juice (I used Realemon)

1/2 tsp butter or margarine to keep jam from foaming

5 1/4 cups granulated sugar

Strawberry Rhubarb Jam Directions:

In a large stainless steel pot (I use my pasta pot), stir together strawberries, rhubarb, lemon juice, pectin and butter.

Strawberries, rhubarb, lemon juice and pectin
Strawberries, rhubarb, lemon juice and pectin

Heat and stir over high heat to a full boil. Add all of the sugar – bring back to a full boil – stirring constantly, and keep heating until the boil cannot be stirred down

(as the Bernardin instructions say – but take care – I have burnt the bottom of my jam over my gas stove at home – so keep an eye on things!}

How to make strawberry rhubarb jam - add the sugar
Add in all the sugar
How to make strawberry rhubarb jam - keep at full boil
Keep the jam at full boil

Keep the jam at a full boil for one full minute. Remove from heat.

How to make strawberry rhubarb jam - keep at full boil
Ready to ladle into prepared jars

Ladle into prepared jars – leaving 1/2 inch headspace or airspace at the top of each jar. Any leftover jam – not filling a jar to the proper airspace can go in an extra jar – and be placed in the refrigerator to enjoy soon.

Heat sealing disks in the warm water. Wipe clean the tops of the glass jars and place the sealing discs over each. Place a sterilized ring over each jar and lid – and tighten to finger tight level.

Place all jars upright back into the water pot – ensuring that water covers each more than an inch. Bring to a boil, and process for 10 minutes. Turn off heat and let sit in water for another 5 minutes. Then remove with tongs (keeping upright) and sit on a cooling rack or tray.

Strawberry rhubarb jam jars
Strawberry Rhubarb Jam Jars

Leave the jars to cool for 24 hours – you should hear a pop from each jar as the lids contract and create a vacuum as they cool.

My Strawberry Rhubarb Jam turned out exactly right – but I wish I had more….. It’s the first preserve of this season, and I’m ready for the Raspberries and Blueberries.

A few more random FAQS:

Why Is rhubarb a vegetable and not a fruit?

Even though rhubarb is typically cooked in sweet desserts and preserves it is actually a vegetable. A fruit develops from the flower or a plant and contains seeds, while other parts of a plant are defined as vegetables – the stalks, roots and leaves. We eat the stalk only of rhubarb.

What part of rhubarb is poisonous?

The leaves of rhubarb are poisonous and should be discarded. They contain oxalic acid. Oxalic acid is also found in Swiss chard, spinach, beets, peanuts, chocolate, and tea by the way – AND there is oxalic acid in the stem – just not as much.

Is rhubarb high in pectin?

There is pectin in rhubarb – but it is not high in pectin.

Is strawberry rhubarb jam better with or without pectin?

It is better with pectin. You will have to cook jam much longer in order to get it to gel without pectin and it may never gel!

red and green glass jars
Photo by Markus Spiske on

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6 thoughts on “Make Homemade Strawberry Rhubarb Jam

  1. I’m inspired by your rhubarb saskatoon compote! I have some saskatoon bushes, but they have some sort of blight – so hopefully I will have some berries next year.

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