Snapdragons are one of those flowers that just make me happy. Their unique dragon mouth blooms have been staples in my garden for years. But I learned the hard way that not everything plays nice with these beauties.
After making mistakes with companion planting I realized that with snapdragons it isn’t just helpful – it’s essential if you want those tall spikes of colorful blooms that make your garden pop you have to pair your snapdragons with care.
Understanding Snapdragons
Snapdragons (Antirrhinum majus) are these wonderful cool-season flowers that can actually bloom from spring through fall in the right conditions. They’re moderate feeders that prefer well-draining soil and need a decent amount of sunlight to really thrive.
But snapdragons can be surprisingly picky about their neighbors. They’re vulnerable to certain pests, susceptible to specific diseases & can get seriously stressed when forced to compete for resources with the wrong companion plants.
When snapdragons struggle you’ll notice it immediately. Their growth becomes stunted, blooms are sparse and those gorgeous colors you were expecting just don’t materialize. In worst-case scenarios, they might not even survive the season.
13 Plants to Keep Away From Your Snapdragons
1. Mint and Other Aggressive Herbs
This is the mistake that ruined my snapdragon display last year. Mint is notorious for being invasive and its aggressive root system will absolutely overtake your snapdragons. The mint literally steals nutrients, water and space from anything nearby.
I planted spearmint about a foot away from my snapdragons, thinking that was plenty of space. Within weeks I could see the mint sending runners toward my flower bed. By mid-summer my snapdragons were being choked out completely.
The same goes for other aggressive herbs like oregano and certain types of thyme. Keep these in contained spaces, preferably in pots, far away from your precious snapdragons.
2. Potatoes
Here’s something many gardeners don’t realize: potatoes and snapdragons both can suffer from verticillium wilt. This soil-borne fungal disease can persist in your garden soil for years, so planting snapdragons where potatoes have grown (or vice versa) is asking for trouble.
3. Tomatoes
Similar to potatoes, tomatoes can host diseases that affect snapdragons. Additionally, tomatoes are heavy feeders that will compete with your snapdragons for nutrients.
Tomatoes also tend to get quite large & can cast unwanted shade on your sun-loving snapdragons. The difference in watering needs creates another point of conflict – tomatoes need consistent moisture while snapdragons prefer to dry out slightly between waterings.
4. Cucumbers and Other Sprawling Vines
Any plant that sprawls or creates a ground cover can be problematic for snapdragons. Cucumber vines, squash, pumpkins and similar plants will quickly take over, stealing sunlight and creating too much humidity around the base of your snapdragons.
5. Sunflowers
While beautiful, sunflowers make terrible neighbors for snapdragons for several reasons. First, they grow incredibly tall and cast significant shade. Second, they’re extremely heavy feeders that will deplete the soil of nutrients your snapdragons need.
Perhaps most importantly, sunflowers exhibit allelopathy – they release compounds from their roots that actually inhibit the growth of certain other plants. This natural chemical warfare can severely stunt your snapdragons’ growth.
6. Gladiolus
This might seem counterintuitive since both are beautiful flowering plants, but gladiolus and snapdragons compete for the same nutrients and are susceptible to many of the same diseases. When planted too close together they can essentially amplify each other’s pest and disease problems.
On top of that gladiolus bulbs (technically corms) need different soil conditions than what’s ideal for snapdragons, creating a situation where neither plant is growing in its preferred environment.
7. Black Walnut Trees
If you have black walnut trees on your property, keep your snapdragons far away from them. Black walnut trees produce juglone, a toxic substance that inhibits the growth of many plants, including snapdragons.
Even if you plant snapdragons outside the canopy of the tree, the roots can extend much farther than the branches, continuing to release juglone into the soil.
8. Taller Dahlias
Dahlias, especially the taller varieties, will outcompete snapdragons for sunlight and can create an overcrowded feel in the garden bed. The heavy watering and rich soil that dahlias prefer can also lead to root rot in snapdragons, which prefer slightly drier conditions.
9. Rhododendrons and Azaleas
These popular shrubs create acidic soil conditions that snapdragons absolutely hate. Snapdragons prefer neutral to slightly alkaline soil, so planting them near acid-loving plants sets them up for failure from the start.
10. Corn
Corn not only creates too much shade for snapdragons, but it also attracts earworms that can infest your snapdragons as well. The heavy feeding nature of corn will leave the soil depleted for your flowers.
11. Fennel
Fennel is another plant with allelopathic properties that can inhibit the growth of neighboring plants. While it’s a beautiful herb with lovely yellow flowers it should be kept well away from your snapdragon beds.
12. Plants That Need Frequent Watering
Any plants that require consistent moisture – like astilbe, ligularia or irises – will create soil conditions that are too wet for snapdragons. This mismatch in watering needs usually results in either struggling snapdragons (if you water for the moisture-loving plants) or wilted moisture-lovers (if you water for the snapdragons).
13. Late-Season Bloomers That Require Division
Plants like asters and mums that bloom late and need frequent division can disturb the root systems of nearby snapdragons when you’re doing maintenance. It’s best to give these plants their own dedicated space where you can divide them without impacting other perennials or replanted annuals like snapdragons.
What To Plant With Snapdragons Instead
Those are the ones to avoid. So here are some plants that make excellent companions for snapdragons:
- Sweet Alyssum: Creates a lovely ground cover that retains moisture without creating soggy conditions.
- Calendula: Attracts beneficial insects that can help control pests that bother snapdragons.
- Lobelia: The blue varieties create a stunning color contrast with bright snapdragon blooms.
- Pansies and Violas: These have similar growing requirements and complement snapdragons beautifully.
- Dianthus: Similar cultural needs make these perfect companions.
Tips for Successful Companion Planting With Snapdragons
- Always consider height – plant taller flowers behind snapdragons, shorter ones in front.
- Check watering needs – group plants with similar moisture requirements.
- Think about bloom times – pair early-blooming snapdragons with plants that will take over the show when snapdragons fade in extreme heat.
- Rotate your plantings – don’t put snapdragons in the same spot year after year to avoid disease buildup.
- Leave enough space – snapdragons look delicate but can get bushy with proper care; don’t crowd them.
Final Thoughts on Snapdragon Companion Planting
Gardening is always part science, part art & a whole lot of trial and error. What works in a Zone 5, 6 etc. garden might need adjustments in your growing conditions. Don’t be afraid to experiment (on a small scale) and find the perfect companions that work in your unique garden.
Just keep those aggressive herbs, heavy feeders and disease-prone vegetables far away from your snapdragons and you’ll be well on your way to a stunning display that will have the neighbors asking for your secrets!