How it works · Quercus

Quercus Score™

Native plants are compared using the wildlife they support and the habitat they provide. All supported states use the same North Carolina native reference group, with state-specific caterpillar records.

Factor	Weight	What it describes
Caterpillars	45%	Species that use the plant’s genus as a larval host.
Bees	20%	Bee species recorded visiting the genus in the Southeast.
Specialist bees	15%	Eastern bees that depend on particular pollen sources.
Birds	10%	Bird species recorded eating seeds, fruit or other plant parts.
Habitat structure	10%	Plant growth form as an indication of cover and nesting space.

The weighted factors are ranked within the reference group. The highest 14% receive baseline scores of 80–100; the remaining scores run from 5–79. Additional recorded insect groups can contribute up to five points, with a maximum score of 100.

Each factor counts by rank, not by size, so a plant near the top for caterpillars gets nearly full credit: white oak’s 496 caterpillar species count only a little more than American holly’s 52. Holly and rosebay rhododendron also have more bee species and specialist bees on record than white oak, which has none, so they score higher overall.

Most wildlife counts describe a genus, so closely related plants can share a score. A plant with few records may simply be less studied. Conservation status describes rarity and protection separately.

Who uses each plant?

Open an animal row to see the available names and interactions. Caterpillar records describe larval food plants; flower visits and ant–seed interactions describe other uses. A visit is not necessarily pollination, and a seed interaction may involve dispersal or consumption.

The records include different geographic areas. Each group keeps its source and regional context.

Fit for your spot

Start with your county, then add sunlight, usual soil moisture and pH. Fit combines that information with ecological value. Unanswered questions stay open.

The starting estimate is 60 + 0.40 × Quercus. The least suitable known condition sets the adjustment: a match keeps the estimate; a mismatch reduces it. A recorded county receives full geographic weight. A recorded neighboring county sharing an ecoregion receives 95%. Without either, the result remains a preliminary estimate.

Fit helps compare planting choices; it is not a survival probability. Check mature size, drainage and your local climate as you plan.

How to check your spot →

Invasive and non-native plants

Listed invasive plants receive negative harm scores and a “Do not plant” recommendation. North Carolina uses its invasive-list ranks. Other states use matched harm profiles where available and −30 for listed invasives without a matched rank. Other non-native plants are not given a positive ecological score.

Reading the bands

Keystone: 80 and up · Strong: 50 to 79 · Good: 20 to 49 · Modest: 5 to 19 · Neutral: −5 to 4 · Harmful: −40 to −6 · Severe harm: below −40.

Sources

Quercus is an evolving index built from published plant and wildlife records.