Herb of the Cross: A Historical Plant with Modern Garden Questions
Ever stumbled across a weedy-looking plant with tiny purple flowers arranged in thin spikes and wondered what it was? You might have encountered Verbena officinalis, commonly known as herb of the cross. This unassuming annual has a fascinating history that spans continents and centuries, but its place in today’s North American gardens is worth some consideration.
What Exactly Is Herb of the Cross?
Herb of the cross (Verbena officinalis) is an annual forb – basically a non-woody plant that completes its life cycle in one growing season. Don’t let its humble appearance fool you; this plant has been treasured throughout history for its supposed medicinal properties and spiritual significance. The name herb of the cross hints at its religious associations in European folk medicine.
Standing 1-3 feet tall with a somewhat sparse, branching structure, this plant produces small purple to lavender flowers arranged in slender, elongated spikes. While it might not win any beauty contests compared to showier garden favorites, it has its own quiet charm.
Where Does It Grow?
Originally from Europe, Asia, and North Africa, herb of the cross has made itself quite at home across much of North America. You can find it growing wild in 27 states, from coast to coast: Alabama, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Mississippi, New Jersey, New Mexico, New York, North Carolina, Oregon, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia, Washington, West Virginia, and Wisconsin.
The plant has established itself so well that it reproduces spontaneously in the wild without any human help – a testament to its adaptability, though not necessarily its desirability in cultivated spaces.
Should You Plant Herb of the Cross?
Here’s where things get interesting. While herb of the cross isn’t classified as invasive in our data, its non-native status and aggressive self-seeding habits give thoughtful gardeners pause. Let’s break down the pros and cons:
Reasons You Might Want to Grow It:
- Historical and cultural significance for herb enthusiasts
- Attracts small pollinators like bees and butterflies
- Extremely low-maintenance once established
- Drought-tolerant and adaptable to poor soils
- Provides some food for wildlife (though modestly)
Reasons You Might Want to Skip It:
- Not native to North America
- Can self-seed aggressively and spread beyond intended areas
- Somewhat weedy appearance may not suit formal gardens
- Native alternatives provide better ecological benefits
Native Alternatives to Consider
Before committing to herb of the cross, consider these native verbena species that offer similar benefits with better ecological credentials:
- Blue vervain (Verbena hastata) – taller with showy blue-purple flower spikes
- Purple-top vervain (Verbena bonariensis) – though technically non-native, it’s less aggressive
- Narrowleaf vervain (Verbena simplex) – native with delicate purple flowers
How to Grow Herb of the Cross
If you decide to give herb of the cross a try, you’ll find it refreshingly easy to grow. This plant practically thrives on neglect!
Growing Conditions:
- Light: Full sun to partial shade
- Soil: Adaptable to most soil types, even poor or compacted soil
- Water: Drought-tolerant once established; avoid overwatering
- Hardiness: Grows as an annual in USDA zones 4-9
Planting and Care Tips:
- Sow seeds directly in spring after the last frost
- Seeds need light to germinate, so barely cover them with soil
- Space plants about 12 inches apart (though they’ll self-seed anyway)
- Water regularly until established, then reduce watering
- Deadhead flowers to prevent excessive self-seeding
- No fertilizer needed – too much nutrition can actually reduce flowering
Wildlife and Pollinator Benefits
While herb of the cross won’t single-handedly transform your garden into a wildlife haven, it does offer some ecological value. The small tubular flowers attract various pollinators, including bees, butterflies, and other beneficial insects. According to research, it provides a modest 5-10% of the diet for both large animals and terrestrial birds, though they don’t typically use it for cover.
A Word About Wetland Status
Interestingly, herb of the cross is classified as facultative upland across all regions of North America. This means it usually grows in non-wetland areas but can occasionally pop up in wetland edges. This adaptability is part of what makes it so successful as an introduced species.
The Bottom Line
Herb of the cross occupies an interesting niche in the gardening world. It’s not inherently bad, but it’s not necessarily the best choice for eco-conscious gardeners either. If you’re drawn to its historical significance or simply like its understated charm, go ahead and plant it – just be prepared to manage its enthusiastic self-seeding habits.
However, if your goal is to support native ecosystems and local wildlife, you’ll get more bang for your buck with native verbena species. They offer similar aesthetics with the added bonus of supporting the insects, birds, and other wildlife that evolved alongside them.
Whatever you choose, remember that gardening is as much about personal enjoyment as it is about ecological responsibility. The key is making informed decisions that align with your values and garden goals.
