When To Plant Rhubarb In Colorado

The best time to plant rhubarb in Colorado is in early spring, as soon as the soil can be worked, typically between late March and mid-April.
 
This timing is crucial because rhubarb needs a period of winter chill to produce sturdy stalks, and getting it in the ground early gives it a full growing season to establish strong roots.
 
If you’re wondering when to plant rhubarb in Colorado, the answer also depends on your specific elevation and how quickly the ground thaws.
 
In this post, we’ll break down the best planting windows, how to prepare your soil, and tips for a thriving rhubarb patch in the Centennial State.
 
Let’s dig into the details so you can enjoy homegrown rhubarb for pies, jams, and more.
 

When to Plant Rhubarb in Colorado: The Ideal Window

When to plant rhubarb in Colorado really comes down to understanding your local frost dates and soil temperatures.
 
Rhubarb is a cold-hardy perennial, so it actually prefers cooler conditions, and it will struggle if planted too late in the heat of summer.
 
The general rule is to plant rhubarb crowns or divisions about four to six weeks before the last expected frost.
 
For most of Colorado’s Front Range, that means late March to mid-April is your sweet spot.
 
However, if you live in the mountains or at higher elevations, you might need to wait until early May for the ground to thaw enough.
 

1. Soil Temperature Matters for Rhubarb

When to plant rhubarb in Colorado is also guided by soil temperature, not just the calendar.
 
Rhubarb roots will start to grow when the soil temperature reaches about 40°F to 45°F.
 
You can use a simple soil thermometer to check, or just watch for when the ground is no longer frozen and crumbles easily in your hand.
 
Planting too early in waterlogged, freezing soil can rot the crowns, while planting too late can stress the plant.
 
If the soil is still soggy from snowmelt, wait a week or two until it drains out.
 

2. Fall Planting Is a Second Option

While early spring is the prime time for when to plant rhubarb in Colorado, you can also plant in early fall.
 
Late September to early October works well because the soil is still warm, but the air is cooling down.
 
This gives the roots a chance to establish before the ground freezes solid in November.
 
Just make sure you plant at least six weeks before the first hard freeze.
 
Fall planting often leads to a stronger harvest the following year since the plant gets a head start on root development.
 

3. Divide Existing Plants for Better Timing

If you already have rhubarb, you might ask when to plant rhubarb in Colorado by division rather than new crowns.
 
The answer is the same early spring window, right when new buds are just emerging.
 
Dig up the mature plant, split the crown into sections with a sharp knife, and replant them immediately.
 
This is a great way to expand your patch, and it’s best done in that same March-to-April timeframe.
 
Dividing in spring gives the new plants the whole season to recover and establish.
 

Preparing Your Colorado Soil for Rhubarb

Once you’ve nailed down when to plant rhubarb in Colorado, you need to prep the soil properly.
 
Rhubarb is a heavy feeder, so it demands rich, well-draining soil.
 
Colorado’s native clay or sandy soils often need amendments before planting.
 

1. Amend With Compost and Aged Manure

Before planting, dig a hole about two feet wide and one foot deep.
 
Mix the excavated soil with a generous amount of compost and well-rotted manure.
 
This boosts organic matter, improves drainage, and provides slow-release nutrients.
 
Rhubarb loves a slightly acidic to neutral pH, around 6.0 to 6.8, which is common in many Colorado gardens.
 

2. Ensure Proper Spacing

When to plant rhubarb in Colorado also involves giving each plant enough room to spread.
 
Space your rhubarb crowns at least three to four feet apart.
 
They can get quite large, and overcrowding leads to poor air circulation and disease.
 
Plant the crown so the buds sit just one to two inches below the soil surface.
 
Burying them too deep can cause rotting, while planting too shallow exposes them to drying winds.
 

3. Water Deeply After Planting

After you’ve set the crowns in the ground, water them thoroughly.
 
Colorado’s dry climate means you’ll need consistent moisture during the first growing season.
 
Give your rhubarb about one to two inches of water per week, either from rain or supplemental watering.
 
Mulching with straw or wood chips helps retain soil moisture and keeps the roots cool in summer.
 
This is especially important because Colorado’s intense sun can dry out the top few inches quickly.
 

Common Mistakes to Avoid When Planting Rhubarb in Colorado

Knowing when to plant rhubarb in Colorado is half the battle, but avoiding these common pitfalls will ensure success.
 

1. Planting Too Late in Spring

If you wait until May or June to plant rhubarb, you’re fighting an uphill battle.
 
The heat can stress immature plants, and they may not establish well before summer’s peak.
 
Remember, when to plant rhubarb in Colorado is early and often, so mark your calendar for late March.
 

2. Harvesting Too Soon

Resist the urge to harvest any stalks in the first year.
 
This is a critical mistake.
 
Your rhubarb needs all its energy to build a strong root system.
 
In the second year, you can lightly harvest a few stalks, but leave the majority to fuel growth.
 
From the third year onward, you can harvest for about eight to ten weeks.
 

3. Forgetting Winter Mulch

While rhubarb is cold-hardy, Colorado’s freeze-thaw cycles can heave crowns out of the ground.
 
After the ground freezes in late fall, apply a thick layer of mulch over the crowns.
 
This insulates them from dramatic temperature swings and prevents damage.
 
Remove the mulch in early spring when you see new shoots emerging.
 

So, When Should You Plant Rhubarb in Colorado?

The best time to plant rhubarb in Colorado is early spring, from late March to mid-April, as soon as the soil is workable.
 
This aligns with the plant’s natural growth cycle and gives it the cold period it needs to thrive.
 
Early fall planting is a solid backup option, but spring remains the most reliable for our unique climate.
 
Just remember to focus on soil prep, spacing, and consistent watering after planting.
 
By getting the timing right and avoiding the common mistakes, you’ll be rewarded with a robust rhubarb patch that yields delicious stalks for years.
 
So, mark your calendar, prep your soil, and get ready to enjoy the tart, tangy goodness of homegrown rhubarb right in your Colorado backyard.