For years, I’ve had plum trees in my garden, and one question always came up: what can I plant underneath them? It’s tempting to leave the ground bare, or just throw down some mulch and call it a day. But I’ve learned that with a little thought, you can turn that under-tree space into a thriving micro-ecosystem that actually benefits your plum tree.
I used to think any plant would do, as long as it looked nice. I made this mistake for years, planting things that either competed too much for nutrients or didn’t offer any real value. What I found was that the best approach isn’t just about aesthetics; it’s about creating a harmonious relationship between your plum tree and its understory companions. Think about what the tree needs and what the other plants can provide.
Understanding Your Plum Tree’s Needs
Before you plant anything, it helps to understand a plum tree’s basic requirements. These are mid-sized trees, typically reaching about 15 feet tall and wide if left unpruned. They need full sun, which means at least six to eight hours a day. If they don’t get enough light, the fruit won’t ripen properly or sweeten up as it should.
Plums also need consistent watering, especially in their first couple of years. I aim for at least 10 gallons per week for a newly planted tree. They’re not particularly fussy about fertilizer when first planted; I just use compost and the soil from the hole. Zone-wise, most plums do well in zones 3 to 8, so they’re quite adaptable.
Asian vs. European Plums
It’s worth noting that there are two main types of plums: Asian and European. Asian plums ripen earlier and are usually juicier, often used for wine or sauces. European plums are meatier, sweeter, and ripen later, often used for drying or preserving. They also bloom at different times, so they typically don’t cross-pollinate each other. This difference in bloom and ripening times means the shade patterns and nutrient demands under the tree might shift slightly throughout the season, which is something to consider for your underplantings.
The Benefits of Thoughtful Underplanting
I’ve seen firsthand how companion planting can make a difference. It’s not just about filling space. When done right, it can:
- Improve soil health: Certain plants can add nitrogen to the soil or break up compacted earth.
- Suppress weeds: A dense groundcover can outcompete weeds, reducing your weeding chores.
- Retain soil moisture: Plants act as a living mulch, keeping the soil cooler and reducing evaporation.
- Attract beneficial insects: Flowers draw in pollinators and predatory insects that can help control pests.
- Enhance aesthetics: Let’s be honest, a well-planted understory looks much better than bare soil or weeds.
Groundcovers and Perennials for Plum Trees
When I’m choosing plants for under my plum trees, I look for things that won’t compete aggressively with the tree’s roots but will still offer benefits. Here are a few categories that have worked well for me:
Nitrogen Fixers
Plants that fix nitrogen from the air into the soil are fantastic companions. This means less need for external fertilizers for the plum tree. Clover is a classic choice. It’s low-growing, spreads nicely, and adds nitrogen. I’ve used white clover, and it forms a soft carpet that also helps keep weeds down. Just be mindful that it can spread, so keep an eye on it if you’re worried about it moving into other garden beds.
Dynamic Accumulators
These plants have deep taproots that bring up nutrients from deeper soil layers, making them available to other plants when their leaves decompose. Comfrey is a popular one. I’ve planted comfrey around the drip line of my plum trees. I cut its leaves a few times a season and just lay them on the soil as a nutrient-rich mulch. It’s a powerhouse for nutrient cycling.
Weed Suppressors
Any dense groundcover will help keep weeds at bay. Besides clover, I’ve had success with strawberries. They spread, create a nice living mulch, and you get an extra crop! Just be sure to give them enough light if your plum tree is still young and not casting much shade. As the tree grows, you might need to select shade-tolerant strawberry varieties or move them. Creeping thyme is another low-maintenance option that smells great when walked on and forms a tight mat.
Flowers and Herbs for Pollinators and Pest Control
Attracting beneficial insects is key, especially for pollination and natural pest control. I always try to include a variety of flowering plants around my fruit trees.
Attracting Pollinators
Borage is a fantastic choice; bees absolutely love it, and it’s also a dynamic accumulator. Its bright blue flowers are a cheerful sight. Calendula is another easy-to-grow flower that attracts pollinators and can help deter some pests. I just sprinkle seeds in spring, and they usually take off.
Pest Deterrents
Some herbs and flowers are known to deter specific pests. Nasturtiums are good for attracting aphids away from your main crop (they act as a trap crop) and are also edible. Garlic chives or onions planted around the base can help deter borers and other soil-dwelling pests. I’ve noticed fewer issues with borers when I have alliums planted nearby.
What to Avoid Planting Under Plum Trees
Just as important as knowing what to plant is knowing what not to plant. I learned this the hard way, trying to squeeze in too many hungry plants.
- Heavy feeders: Avoid planting other fruit trees or large, hungry shrubs directly under the plum tree. They’ll compete too much for water and nutrients.
- Plants that require a lot of disturbance: Avoid anything that needs frequent digging or root disturbance, as this can harm the plum tree’s shallow feeder roots.
- Black walnut trees: These produce juglone, a chemical that is toxic to many plants, including most fruit trees. Keep plum trees and their underplantings far away from black walnuts.
- Aggressive spreaders: While some spreaders are good for groundcover, avoid extremely vigorous ones that could choke out your plum tree, especially when it’s young. Do your research on a plant’s growth habits.
Practical Tips for Success
Here are a few things I keep in mind when establishing an understory garden around my plum trees:
- Start small: Don’t try to plant everything at once. Pick a few companions and see how they do. You can always add more later.
- Observe: Pay attention to how your plants are growing. Is the plum tree showing signs of stress? Are the companion plants thriving? Adjust as needed.
- Mulch first: Before planting, I often lay down a good layer of compost and then mulch around the plum tree, leaving a small space around the trunk. This creates a good base for the companion plants and helps retain moisture.
- Water wisely: Remember that young companion plants will also need water. Make sure everyone is getting enough, especially during dry spells.
- Consider shade: As your plum tree grows, the amount of shade underneath will increase. Choose plants that can tolerate partial shade or plan to move sun-loving plants to a different spot as the canopy expands.
Creating a thriving understory beneath your plum tree is a rewarding process. It’s about building a mini-ecosystem that supports your tree and adds beauty and productivity to your garden. By understanding the plum tree’s needs and selecting beneficial companions, you can turn that often-overlooked space into a valuable part of your orchard.
What Works for Me
I’ve found that a combination of white clover for nitrogen and groundcover, comfrey for nutrient cycling, and a mix of borage and calendula for pollinators works exceptionally well. This approach keeps the soil healthy, reduces weeding, and ensures my plum trees get plenty of bee visits. It’s a low-maintenance system that consistently yields good results, and I rarely buy beans from the store anymore, thanks to the improved soil. Give it a try; you might be surprised at the difference it makes.
