Understanding Cone Development and Color Variation in Techny Arborvitae

Light green "buds" covering Techny arborvitae (Thuja occidentalis 'Techny') in late season are immature seed cones — a normal reproductive stage, not a problem. Color variation between heavily coning and lightly coning plants reflects energy allocation differences.

Cone Development Timeline

• Spring: Pollen cones (male) and seed cones (female) emerge.
• Summer: Seed cones expand, green and fleshy.
• Fall: Cones mature to brown, woody structures.
• Winter: Cones open, releasing seeds; persist on branches.

Addressing the Pale, Heavily Coning Plant

The lighter green foliage on the cone-heavy plant indicates energy diversion to reproduction. Corrective steps:

• Increase watering: Twice weekly (5+ gallons each) to support both cone maturation and foliage health.
• Stop fertilizing: No more Miracid or any fertilizer until fall. Excess nitrogen during coning stresses the plant.
• Monitor: Foliage color should normalize after cone maturity.

Long-term Perspective

Heavy coning years are cyclical. Next year may show minimal cones and darker foliage. Techny arborvitae is naturally a lighter green than some cultivars — the "sickly" appearance is often just cultivar character amplified by reproductive effort.