North America Native Plant

Hybrid Oak

Botanical name: Quercus ×grandidentata

USDA symbol: QUGR4

Life cycle: perennial

Habit: tree

Native status: Native to the lower 48 states  

Hybrid Oak: A Rare California Native Worth Knowing About Meet the hybrid oak (Quercus ×grandidentata), one of California’s most elusive native trees. If you’ve never heard of this particular oak, you’re not alone – it’s so rare that even seasoned native plant enthusiasts might scratch their heads when you mention ...

Rare plant alert!

Region: Conservation status by state

Status: S1S3: Status is uncertain but is somewhere between the following rankings: Critically Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 5 or fewer occurrences or very few remaining individuals (<1,000) ⚘ Vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals ⚘

Hybrid Oak: A Rare California Native Worth Knowing About

Meet the hybrid oak (Quercus ×grandidentata), one of California’s most elusive native trees. If you’ve never heard of this particular oak, you’re not alone – it’s so rare that even seasoned native plant enthusiasts might scratch their heads when you mention it.

What Makes This Oak Special?

The hybrid oak is exactly what its name suggests – a natural cross between two oak species that has resulted in something quite unique. As a perennial tree, it follows the classic oak blueprint: a single sturdy trunk that can reach impressive heights of over 13-16 feet, and in ideal conditions, much taller than that.

What sets this tree apart isn’t just its hybrid nature, but its incredible rarity. With a conservation status of S1S3, this oak falls into a category that conservation biologists keep a close eye on.

Where Does It Call Home?

This native beauty is found exclusively in California, making it a true Golden State endemic. Its limited range is part of what makes it so special – and so rare.

Should You Plant a Hybrid Oak?

Here’s where things get a bit complicated. While this oak is undoubtedly a fascinating native species, its rarity means you need to be extra thoughtful about how you approach growing one.

The Reality Check

Let’s be honest – finding a hybrid oak for your garden is going to be like searching for a needle in a haystack. Commercial nurseries rarely (if ever) carry this species, and for good reason. Its rarity means that any specimens should be carefully managed and sourced responsibly.

If You’re Determined to Grow One

Should you somehow locate a hybrid oak, here are the key considerations:

  • Source responsibly: Only obtain plants from reputable native plant nurseries that can verify the plant’s provenance
  • Understand the commitment: Like all oaks, this is a long-term relationship – these trees can live for centuries
  • Prepare for mystery: With limited cultivation information available, you’ll be somewhat pioneering in your care approach
  • Think about space: As a tree species, it will need room to grow and develop its natural form

Growing Conditions and Care

Since specific growing information for hybrid oak is scarce, your best bet is to follow general California native oak care guidelines:

  • Plant in fall or early winter when rains typically begin
  • Provide well-draining soil – oaks despise soggy feet
  • Once established, avoid summer watering near the trunk
  • Give it plenty of space to develop its natural canopy
  • Be patient – oaks are notoriously slow growers

Alternative Options

If you’re drawn to the idea of a rare California oak but can’t locate a hybrid oak, consider these more available native alternatives:

  • Valley oak (Quercus lobata) – California’s largest oak
  • Coast live oak (Quercus agrifolia) – evergreen and iconic
  • Blue oak (Quercus douglasii) – drought-tolerant and beautiful

The Bottom Line

The hybrid oak represents something special in California’s plant world – a rare natural hybrid that reminds us of the incredible diversity hiding in our native landscapes. While it’s unlikely you’ll be planting one in your backyard anytime soon, knowing about species like this helps us appreciate the complexity and wonder of our native plant communities.

Sometimes the most valuable plants are the ones we simply know about and protect, rather than the ones we grow ourselves. In the case of hybrid oak, contributing to conservation efforts and supporting organizations that protect rare plants might be the best way to help ensure this unique tree continues to thrive in its California home.

Hybrid Oak

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Hamamelididae

Order

Fagales

Family

Fagaceae Dumort. - Beech family

Genus

Quercus L. - oak

Species

Quercus ×grandidentata Ewan (pro sp.) [dumosa × engelmannii] - hybrid oak

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA