The Secret to Cold-Hardy Fig Trees: Lignification Explained

After harsh winters, fig trees can experience dieback, where the above-ground wood dies, forcing the tree to regrow from the base. However, once established, figs are surprisingly resilient—almost like weeds.

It breaks my heart that most fig growers don’t realize heavy winter dieback significantly reduces the chances of their fig tree producing fruit the next season.

Related: Fig Tree, NO FRUIT - Grow Figs Not Leaves | The 4 Reasons Why Your Fig Tree IS NOT Fruiting

In this article, I’ll cover a fig tree’s cold tolerance, hardy fig varieties, and lignification—the secret to making your fig tree more cold-hardy.

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Fig Tree Cold Tolerance

Most fig varieties can withstand temperatures as low as 5F and only a rare few can endure 0F. As a result, fig trees can be grown in USDA hardiness zones 5A-6B with winter protection, 7A without protection (though it’s still recommended), and 7B or higher, where winter protection is usually unnecessary.

In each growing zone, I recommend slightly different winter protection strategies to save you a lot of time, money, and heartbreak.

Check out that guide, here: Fig Trees in Zones 5, 6, & 7: A Masterclass on Hardy Fig Trees in Cold Climates

A key question for growers in these zones is: Can they be pushed past their limit of 0F? Could it be that long-term annual winter protection might not be necessary for growers in zone 6? I’ve been on a mission to figure that out. The truth is, there is no definitive answer yet.

Keep in mind that fig tree roots are more vulnerable to cold than the branches. They can suffer damage when temperatures drop below 10-15F. In colder zones, be sure to cover the soil with mulch to help insulate the roots during winter. If you're growing fig trees in pots, bring them indoors to a winter storage area to protect them from damaging temperatures.

Related: Fig Tree Winter Storage - A Necessary Step Toward Survival & Fruiting

Choosing Cold Hardy Fig Varieties

For growers in colder climates, choosing a cold-hardy fig variety can be very helpful. Chicago Hardy remains the gold standard, reliably surviving 0F and producing fruit even after winter dieback.

However, several lesser-known varieties offer excellent cold tolerance, such as Celeste, Florea (Michurinska 10), Teramo, St. Martin, Campaniere, Dalmatie, and Longue d'Aout, all of which have demonstrated resilience in temperatures as low as 0F or lower. As testing continues, the goal is to identify even hardier figs that can extend the range where these trees can thrive with minimal winter protection.

Related: Cold-Tolerant Fig Trees

The Key Factor: Lignification

Through years of observation, I’ve learned that a fig tree’s cold hardiness isn’t just about variety—more importantly, it’s about lignification.

Lignification is the process by which plant tissues become woody and rigid due to lignin deposition in cell walls. This transformation is crucial for cold resistance because it:

• Reduces Water Content in Cells – Less water means a lower risk of cell rupture from freezing.

• Strengthens Cell Walls – Reinforced structures better withstand ice formation and temperature fluctuations.

• Enhances Overall Cold Resistance – A well-lignified fig tree can endure lower temperatures than one that hasn’t properly hardened off.

Fig trees grown outside their native regions often exhibit impaired lignification. Therefore, you may never realize the genetic potential of your fig variety.

The photos above illustrate the damage fig branches sustain after exposure to cold temperatures when they're not lignified properly. The base of the tree shown in the photo is on the left to the highest point shown in the photo on the right.

Lignification progresses over time, with the lower sections typically more lignified than the upper ones. In the first photo, you can observe desiccation, where ruptured cells cause damage to the bark and cambium beneath it. As you move higher up the tree, the desiccation is further progressed, with the branches taking on a redder-brown hue. In the final image, the wood is fully desiccated, turning a deep maroon color.

Important lignification tips:

1. After a new leaf on a fig tree forms, it takes about 3-4 months for optimal lignification.

2. Fig trees won't lignify much further after the first hard frost. Lignification will resume in the spring.

Therefore, new fig tree growth must cease 3–4 months before frost, allowing it to become as lignified and resilient as possible before facing the potentially harsh winter conditions.

Lignification vs. Hardy Fig Varieties

Many growers turn to cold-hardy varieties like Hardy Chicago for better winter survival, but even the toughest fig will suffer from winter damage if it lacks proper lignification. A poorly lignified Hardy Chicago may take severe damage at 20–25F, while a well-lignified tree of a less hardy variety could survive much lower temperatures.

Ultimately, while genetics play a role, lignification depends on environmental conditions, pruning practices, and winter protection. Understanding and encouraging this process is the key to growing truly cold-hardy fig trees.

Strategies to Improve Lignification and Cold Tolerance

To improve lignification and enhance winter survival, fig growers should implement the following practices:

1. Provide Winter Protection for One to Two Seasons - Protect young or weakly lignified fig trees until they develop proper cold resistance.

2. Gain an understanding of a Fig Tree's Hormones and How Pruning Affects Them.

Fig trees regulate their growth, lignification, and fruiting through a delicate balance of hormones, particularly auxins and cytokinins. These hormones influence node spacing, with closer nodes indicating a better balance that favors fruit production over excessive vegetative growth. 

Improper pruning or winter damage can disrupt this balance, causing vigorous, non-fruiting shoots (water shoots) to emerge:

• Over-pruning or excessive winter damage causes fig trees to continue growing late into the season, not giving them the required 3-4 months to lignify before dormancy.

• Proper pruning and winter protection allow trees to lignify earlier, cease growth in summer, and become hardier over time.

Related: Pruning Fig Trees | How Much to Prune & How to Keep Them Small

By strategically managing pruning and protecting young trees from severe cold, growers can help maintain hormonal stability, ensuring stronger lignification, better cold resistance, and ultimately, more productive fig trees.

Pruning Fig Trees for Better Production & Lignification

Here's how to prune fig trees to ensure good lignification, production, and hormonal balance:

1. Avoid heading cuts that shorten the branches. 

• By shortening a branch by 33%, 50%, or 90%, this kind of pruning can lead to excessive growth the following growing season. 

• Sometimes reaching even 7-10 ft in one year and having difficulty producing fruit. 

• On these fast-growing branches, you’ll note a wide node spacing multiple inches apart.

• Instead, use thinning cuts by removing an entire branch flush with the growth below, leaving nothing behind to reduce the tree's size or better light penetration without stimulating excessive regrowth.

  
  

  • The top third of a fig tree’s new growth contains buds with a better hormonal balance for fruiting. Lower buds tend to be more vegetative, leading to excessive growth without fruit.

Image credits to: UC Marin Master Gardeners

Most new fig growers aren't aware that fig trees don't require annual pruning unless they are very old (30-50 years) or too tall. Sometimes, no pruning at all or limiting it to the removal of the apical buds on each branch is all that’s necessary.

Related: What Happens If You Don’t Prune a Fig Tree?

To maintain the desired size and shape, focus on removing a single trunk (for bush-form trees) or scaffold branch (for tree-form structures) each year. A new scaffold or trunk will grow in its place. This recycling process helps maintain a consistent height and size.