Experimental / watchlist · Seed-family seedling

Colossal Family

Not currently offered. We will list it only if quality seed becomes available, and only with full disclosure of its limits.

Species	Castanea sativa x crenata
Seed parent origin	California hybrid, the standard of the West Coast commercial chestnut industry.
Nut size	Very large
Ripening window	Mid season
Cold hardiness	Zone 6, marginal in Iowa
Blight resistance	Poor. Colossal is notably blight susceptible
Best for	Not currently offered.

About this seed family

Colossal produces some of the largest, best-looking chestnuts grown commercially, which is why people ask for it by name.

It is also blight susceptible and marginal for Iowa winters, which is why it is on our watchlist instead of our shelf.

If we do offer it, it will be labeled clearly as a trial planting for sheltered sites only.

What you are actually buying

This is a seedling grown from a nut produced by a named Colossal Family parent tree. It is not a grafted clone and we will never sell it as one. It inherits roughly half its genetics from that known mother tree and half from whatever pollinated her, which means you get a real head start on quality plus the seedling advantages of a natural taproot, lower cost and genetic diversity across your planting.

Every tree is started in our insulated shed under grow lights and grown in a 4 inch by 12 inch deep tree pot, so you receive a well-rooted young tree with a developing taproot rather than a root-bound plug.