Donaldson Orange and Other HLB-Tolerant Citrus Varieties: A Florida Grower's Guide

Citrus greening — known to researchers as Huanglongbing, or HLB — has reshaped Florida citrus more than any freeze or hurricane in living memory. Since the disease was first confirmed in the state in 2005, it has been tied to roughly a 90% drop in citrus production, and there is still no cure. So for anyone planting orange trees today — whether you're establishing a single backyard tree or a new grove block — one question matters more than any other: which varieties can live with HLB and keep producing?

The encouraging news is that researchers at UF/IFAS and USDA-ARS have spent two decades identifying and breeding citrus that tolerates greening. At North Florida Citrus Nursery, we build our catalog around that science. Below is a practical, grower-focused look at the Donaldson orange and the other HLB-tolerant varieties worth knowing.

Tolerance vs. Resistance: An Important Distinction

Before naming varieties, it helps to be clear on terms, because they get used loosely online.

• Resistant would mean a tree does not get infected. No commercial sweet orange is truly immune to HLB.
• Tolerant means a tree can become infected and still stay healthy and productive for years, rather than declining and dying.

Every variety in this guide is tolerant, not immune. Tolerance is what makes a tree plantable in an HLB world — but it still depends on good care, clean nursery stock, and psyllid management to reach its potential.

The Donaldson Orange: A Rediscovered Survivor

The Donaldson sweet orange is the variety generating the most excitement in Florida citrus circles right now, and for good reason.

USDA-ARS scientists at the U.S. Horticultural Research Laboratory in Fort Pierce rediscovered Donaldson in 2021 at the A.H. Whitmore Foundation Farm in Groveland, Florida — a single mature tree in a block originally planted back in 1986. While the industry-standard trees around it declined or died, the Donaldson tree stood out as remarkably healthy. Notably, it tested positive for the HLB bacterium (Candidatus Liberibacter asiaticus) yet kept thriving — the signature of genuine tolerance: infected, but unbothered.

What growers should know about Donaldson:

• Type: Early-season sweet orange, maturing roughly December to January.
• Use: A potential replacement for Hamlin in not-from-concentrate orange juice. Early taste tests have been promising.
• Fruit: Resembles a typical seedy sweet orange.
• Status: Still being confirmed. HLB tolerance is hard to prove from a single original tree, so USDA is now establishing replicated field trials. Donaldson is a variety to watch closely rather than one you'll find at every nursery yet.

Donaldson is a reminder that some of the best answers to greening were already growing in Florida soil — they just needed to be found.

Other HLB-Tolerant Varieties Worth Planting

Donaldson may be the newest headline, but several tolerant varieties are already available and field-proven. Here's how the leading options compare:

Sugar Belle®

Perhaps the standout success story. Sugar Belle is widely considered one of the most HLB-tolerant cultivars known in Florida. It's a mandarin hybrid with Minneola-like flavor, and — importantly for us — it performs especially well in North Florida, where growers avoid the soft-fruit problems that can affect it further south. Well-established trees tolerate temperatures down to around 14°F.

Bingo®

An easy-peel, seedless mandarin with excellent flavor and good HLB tolerance that matures very early. Growers should know it can present tree-establishment and dieback challenges, so give it attentive care in its first years.

Marathon

A seedless, easy-peel mandarin with good color and flavor and solid HLB tolerance. It matures early but holds on the tree longer than Bingo, stretching out your harvest window.

US Early Pride & Tango

Both are nearly seedless mandarins from the Fallglo family of selections. Of the two, Tango tends to show stronger HLB tolerance and offers excellent internal color — it keeps cropping even while showing some symptoms of the disease.

B9-65 Valencia

For juice-orange growers, this UF Valencia selection posted the best yield and soluble solids among 30 varieties in long-running trials, with evidence of better performance under HLB than conventional Valencia. It's available to growers now.

US Sun Dragon

A USDA release that is orange-like and HLB-tolerant, with real potential for the juice market — another option as Florida rebuilds its processing base.

The Newest UF/IFAS Releases

UF/IFAS breeders recently released a set of new greening-tolerant selections aimed largely at the juice industry, including an improved-Brix Hamlin (N14-10), two OLL sweet oranges, mandarin hybrids for juice blending, and a new HLB-tough rootstock. These represent the next wave of tolerant genetics moving into the pipeline.

Why North Florida Has an Edge Against Greening

Here's something that doesn't get said enough: geography itself is a tool against HLB.

The Asian citrus psyllid — the insect that spreads greening — and the disease it carries are most aggressive in the warm, frost-free conditions of Central and South Florida. Cooler North Florida winters slow psyllid activity and disease progression, and several tolerant varieties (Sugar Belle chief among them) simply produce better fruit up here.

That's the whole idea behind North Florida Citrus Nursery: growing citrus outside the traditional belt to lower disease pressure from the very start. Pair a tolerant variety with a cooler climate and clean nursery stock, and you've stacked the deck in your favor before the tree ever goes in the ground.

Giving a Tolerant Tree Its Best Start

Tolerance is a head start, not a free pass. To get the most from any HLB-tolerant tree:

• Start with certified, disease-free nursery stock. Every tree we sell is grown to Florida (FDACS) nursery standards.
• Manage psyllids with appropriate controls, especially on tender new flush.
• Feed consistently. Healthy, well-fertilized trees tolerate HLB far better than stressed ones.
• Water wisely — steady moisture without waterlogging.
• Choose the right rootstock for your soil and site.

Frequently Asked Questions

Is any orange tree completely immune to citrus greening? No. There is no truly immune sweet orange. The best available option is a tolerant variety that stays productive despite infection.

Can I buy a Donaldson orange tree now? Donaldson is still in the field-trial and evaluation stage with USDA-ARS, so it isn't widely available commercially yet. It's the variety to watch — reach out and we'll keep you posted as new tolerant selections become available.

What's the best HLB-tolerant tree for a backyard in North Florida? Sugar Belle is a top pick — highly tolerant, cold-hardy once established, and it produces excellent fruit in our climate.

Does HLB-infected fruit hurt people? No. The bacterium that causes greening does not affect human health, and the fruit is safe to eat.

Plant with Confidence

HLB changed Florida citrus, but it didn't end it. Between rediscovered survivors like Donaldson, proven performers like Sugar Belle, and a growing pipeline of UF/IFAS and USDA releases, growers finally have real choices. Add the natural advantage of North Florida's cooler climate, and there's every reason to plant.

Browse our selection of HLB-tolerant and cold-hardy citrus trees — grown right here in North Florida, with statewide shipping and local pickup available.