Companion Planting for Dahlias

MissyWeitzel · 2025-01-30T01:49:48+00:00

I would love to hear a little about how and what you purposefully companion plant with your dahlias. I grow a whole lot of other things in the vicinity of my...

GalenaB

I've done a lot of marigolds as the slugs prefer those and leave my dahlias alone, and also amaranth on the ends as trap crops for cucumber beetles. KaleLane posted somewhere that she does Sweet alyssum to keep away aphids and ever since she started underplanting with that, she's had zero aphid issues. I might trial that one out this year as well, although I don't typically don't deal with a lot of aphids.

Justafewdahlias

GalenaB That is so cool! I just found out it is one of the flowers known to attract beneficial insects like ladybugs and hoverflies.

“Sweet alyssum flowers attract beneficial insects, which then move on to other plants in the vicinity,” said Mauch. “Having sweet alyssum as a food source could help to enlarge beneficial insect populations, providing more opportunity for these beneficial insects to attack pests.”

So they go to the sweet alyssum buffet and set up a home near the conveniently located dahlias!

I already was planning on planting loads of it because I have empty patches in my landscaping garden beds and the scent is so pleasant! This makes me want to try it out to plant in my dahlia beds as well!

Teddahlia

There are aphids and aphids that like dahlias. The ones that like dahlias not very common here. The other ones only occasionally get on the dahlias and after you physically remove them they do not return. They like other species of plants. If you get some aphids from cuttings shipped to you, they are the bad kind. Get rid of them immediately and thoroughly or you will be sorry.

blown_dry

Teddahlia Aphids can do asexual reproduction when it suits them so yeah. "Since the eggs inside a female aphid begin to develop immediately after ovulation, adult female aphids are filled with unborn female nymphs that already have developing eggs inside of them. This phenomenon is called “telescoping of generations”. In essence, the female nymphs are born already pregnant, allowing the population to boom."

Justafewdahlias

Krista That is also kind of similar to my plan. Things I might not want a huge amount of but would be great for attracting beneficial insects. This article from a college extension center breaks down the different groups of plants that attract beneficial insects and lists examples from each. It also discusses some study results on the topic. My plan is a bit of a chaotic plan of planting yarrow, ammi, sweet alyssum (which I already have lots of growing around since I love the smell) and the small type of marigold listed. Sticking them on edges and borders of beds and seeing how that works out. I found it interesting that it was one specific type of marigold where I previously assumed it was all marigolds.

https://hort.extension.wisc.edu/articles/plant-flowers-to-encourage-beneficial-insects/

Krista

Justafewdahlias Oh this sounds very much like my plan, I bet your dahlia beds will be beautiful! And I, also, have since wisened up about Tagetes patula being the proper marigold variety for pest control. I miss the gems though, they’re so pretty in bouquets and I like the way they smell vs the French marigolds I’ve been growing.

Justafewdahlias

My idea is snapdragons, they seem to grow decent even when crowded and don’t attract many pests. You could plant a group 1 and have it finish (I think) before dahlia planting time, or close to it. Or the varieties that bloom in the summer could be shaded by the dahlias since they like cooler temps I believe. I have asiatic Lillies I stuck into half of a small dahlia bed (out of total lack of space and needing to get the bulbs in the ground…but this bed I plan to not use for dahlias next year) soooo I will report back on how that works out 😅😅 All totally untested theories 😂

Krista

DarcyD This is so cool, thank you for sharing! With our move to a new grow zone, and the first summer we’ll be seriously planting edible crops, this is hugely helpful, thanks again for posting this!

Justafewdahlias

I totally forgot to include what I DID successfully interplant: buckwheat! I did it near the end of the season to try to add some nutrients to my soil…..buttttt I totally forgot to chop it down before it flowered (which I guess is what you should do if your using it for that purpose). However, I still liked it as a filler flower/foliage. It is soooo fast from seed to bloom. I threw handfuls and covered it with scraps of row cover and some rocks haphazardly between the dahlias. It even grew in part shade just fine. Added bonus I didn’t know about till after the fact: It is supposed to attract beneficial insects as well. My young child also had loads of fun using his scissors to cut it down and collect seeds from it….a great way to keep him occupied and away from the things he isn’t supposed to cut. Also very shallow easy to pull up roots for me, I would knock over or pull plants out while weeding. I’m sure there are cooler flowers that would also work, but this one I did try and it worked

calico20hill

Juliarugula I totally love the idea of scented leaf geraniums at the ends of the rows! I'm going t0 go order mine right now!

SteveM

Every year I have a lot of extra dahlia tubers so I plant some in my rows of tomatoes. Since dahlia tubers are a preferred food of pocket gophers, at the end of the season the dahlias are gone but the tomato plants are still standing. When I don't use dahlias as distractions the tomato plants don't survive the gopher's buffet parties.

calico20hill

SteveM Clever, Steve! What ever it takes! We are doing 2 more raised beds for veggies this year...they will have rat wire on the bottom. So far that has worked for us. There is a large population of moles or gophers that push up mounds wherever it gets wet, but so far have not seen plant damage so ithink it is moles. I can't dig in this clay but those little guys just zip right through it!

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