This season tested every protea grower on Hawaiʻi Island. Kīlauea’s rhythm—35 eruptive episodes since December 2024—sent recurring SO₂ plumes over our fields. Ocean View took repeated direct hits; Kona absorbed pulse after pulse; on wind reversals, Hilo felt the haze. The impact was stark: one Ocean View farm lost an entire block; many more reported browned bracts, tip dieback, stalled buds, and thinner harvests. Naming the loss matters. We composted stems that should have shipped, cut back promising blocks, and watched bloom waves slip out of sync. Yet within the damage, a steady truth held: farmers adapt.
What Vog does—and why Protea feels it first
Vog forms when sulfur dioxide turns into acidic droplets and sulfate aerosols. These particles cling to leaves and enter through stomata, causing a surface burn and internal toxicity at once. Protea and Leucadendron clearly demonstrate this: crisped margins, bronzing, shortened internodes, and windward canopies that appear scorched. Cuticles roughen, stomata misfire, and plants wilt even with adequate soil moisture. Repeated deposition nudges near-surface pH and can mobilize metals that aggravate proteoid roots, inviting dieback and disease. Flower development takes the first hit: buds stall or abort, bracts bronze early, colors dull, stems finish shorter, and bloom timing turns uneven—fewer, smaller, less market-ready stems until clean-air windows return.
Where impacts concentrated
- Ocean View (Kaʻū): Prolonged exposure drove rapid decline in young blocks and heavy losses in mature plantings; one block was a total loss.
- Kona: Intermittent pulses accumulated into chronic stress—reduced yields, browned bracts, tip dieback on sensitive cultivars.
- Hilo (exposed slopes): On reversal days, symptoms appeared fast—bronzed flushes, tip burn, and uneven opening.
What worked on the ground
- Timely rinses: Freshwater washes right after high-SO₂ days reduced surface acidity and protected cuticles.
- Gentle buffering: Low-rate bicarbonate or calcium sprays moderated leaf-surface pH without adding burn.
- Exposure management: Windbreaks, strategic shade, and selective pruning softened plume-facing scorch.
- Soil steadiness: Suitable pH, sharp drainage, moderated nutrition (especially phosphorus), and strict Phytophthora hygiene curtailed secondary losses.
No single tactic was a cure. During persistent high SO₂, even best practices bent. But they bought time, preserved framework wood, and protected future flushes.
Reading the canopy
Scouting remained essential. Look for a crisp brown band on windward tips, bronzed or puckered new growth, shortened internodes, and bracts that open dull, as if smoked. Outer canopies take the brunt; inner foliage can mask whole-plant stress. Side-by-side photos—wide for context, close for detail—paired with dates, wind, and cultivar created a shared language for action across farms.
Market reality—and a path forward
Paradoxically, the same vog that cut yields lifted demand. With South African and Australian supplies seasonally tight and logistics still uneven, wholesalers chased clean Hawaiʻi stems, and prices firmed for premium grades. For growers worldwide, this is the signal: resilience pays. Protect framework wood now to capitalize when clean-air windows return. Sequence pruning to stagger flushes across risk periods. Diversify blocks by elevation and aspect; pair sensitive cultivars with more tolerant Leucadendron to keep boxes full. Invest in postharvest: hydrate fast, use anti-ethylene where appropriate, and grade hard—vog-marked bracts won’t hide in export light.
Collaboration proved decisive. Island growers shared symptom photos, SO₂ alerts, and spray timings; that network turned confusion into coordinated action. Beyond Hawaiʻi, we invite the Protea International Association to formalize a vog and air-quality grower bulletin, with simple thresholds for rinsing, buffering, and harvest deferral.
We close the year with fewer stems but stronger systems. The lesson is not just about loss—it’s about resolve. Under volcanic skies, protea still teach us to build structure, protect roots, and time our work to the wind. Clean air will return. Be ready to meet the market when it does.
Author
Patio Nelson
Hawai’i Delegate
Protea International Association