North America Native Plant

Hemlock Dwarf Mistletoe

Botanical name: Arceuthobium tsugense tsugense

USDA symbol: ARTST2

Life cycle: perennial

Habit: subshrub

Native status: Native to Alaska âš˜ Native to the lower 48 states  

Hemlock Dwarf Mistletoe: The Tiny Parasite You Don’t Want in Your Garden If you’re a Pacific Northwest gardener with beautiful hemlock trees on your property, there’s a tiny troublemaker you should know about: hemlock dwarf mistletoe. This native plant might sound charming, but it’s actually a parasitic species that can ...

Hemlock Dwarf Mistletoe: The Tiny Parasite You Don’t Want in Your Garden

If you’re a Pacific Northwest gardener with beautiful hemlock trees on your property, there’s a tiny troublemaker you should know about: hemlock dwarf mistletoe. This native plant might sound charming, but it’s actually a parasitic species that can seriously damage your beloved conifers.

What Exactly Is Hemlock Dwarf Mistletoe?

Hemlock dwarf mistletoe is a perennial parasitic plant that makes its living by latching onto hemlock trees and stealing their nutrients. Unlike the festive mistletoe you might hang during the holidays, this little freeloader is barely noticeable – until it starts causing problems for its host tree.

This sneaky parasite appears as small, yellowish-green to reddish shoots that emerge directly from hemlock branches. It’s a low-growing shrub that typically stays under 1.5 feet tall, though it can occasionally reach up to 3 feet in height when conditions are just right.

Where You’ll Find This Unwelcome Guest

Hemlock dwarf mistletoe is native to the Pacific coast, naturally occurring in Alaska, California, Oregon, and Washington. It thrives in the same cool, moist conditions that make hemlock trees so happy – which unfortunately makes it perfectly suited to many Pacific Northwest gardens.

Why You Definitely Don’t Want to Grow This Plant

Here’s the thing about hemlock dwarf mistletoe – you can’t actually cultivate it in a traditional sense, and you wouldn’t want to anyway. This parasitic plant:

  • Weakens and can eventually kill hemlock trees
  • Causes abnormal branch growth called witches’ brooms
  • Reduces the overall health and vigor of infected trees
  • Spreads to nearby hemlock trees through sticky seeds
  • Offers no ornamental value or garden benefits

Spotting the Troublemaker

Keep an eye out for these telltale signs of hemlock dwarf mistletoe infection:

  • Small, segmented shoots growing directly from hemlock branches
  • Yellowish-green to reddish coloration on these shoots
  • Dense clusters of abnormal branching (witches’ brooms)
  • Overall decline in tree health and vigor
  • Premature needle drop in infected areas

What to Do If You Find It

If you discover hemlock dwarf mistletoe on your property, don’t panic – but do take action. The best approach is to remove infected branches at least 12 inches below the visible infection. This helps prevent the parasite from spreading further up the branch or to other trees.

For severe infections, you might need to consult with a certified arborist who can assess whether the tree can be saved or if removal is the best option to protect other hemlocks in your landscape.

The Silver Lining

While hemlock dwarf mistletoe isn’t something you’d want to encourage in your garden, it does play a natural role in forest ecosystems. In wild settings, it creates diverse habitat structures and provides food for some wildlife species. However, in managed landscapes where you’re trying to maintain healthy trees, it’s definitely considered a pest.

The key is understanding that just because something is native doesn’t mean it belongs in every garden situation – sometimes Mother Nature’s plans don’t align with our landscaping goals!

Hemlock Dwarf Mistletoe

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Santalales

Family

Viscaceae Batsch - Christmas Mistletoe family

Genus

Arceuthobium M. Bieb. - dwarf mistletoe

Species

Arceuthobium tsugense (Rosend.) G.N. Jones - hemlock dwarf mistletoe

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