Have you ever wondered what companion planting was all about? Well, let's find out.
Hi, i'm Tim with Shades of Green Nursery and Landscape in Frisco, Texas and I recently gave
a presentation about companion planting to the Frisco Garden Club, so let's check it out. Today
we're going to talk about companion planting and more specifically, what is it. Now, that seems
like a simple question, but a easy answer to it can be hard to find, especially if you go straight
to the internet. If you go to Google, you'll see that there's all kinds of charts out there for
companion planting with vegetables, or herbs, or flowers, or flowers and herbs, or flowers and
vegetables, and on and on it goes. When you go to Pinterest it's even more confusing because there's
even more charts and graphs and tables there that you can find. So, it leads one to wonder,
well, what exactly is companion planting and how do you go about doing it or get started? Well,
the simple answer is that companion planting means different things to different people. But for the
purpose of this presentation, we need to agree on a definition. So, companion planting - what is it?
Grouping plants so that they benefit each other in some way. That seems pretty simple,
which leads the next question - will benefit how? Well, there are several ways they can benefit.
They could benefit aesthetically, by contrasting or complementary color, texture, or size, or even
by seasonality. What do we mean by seasonality? Here's an example from my own backyard.
I grow daffodils and Texas lantana in the exact same spot because they have completely different
time frames. They grow in different seasons. Lantana will come up in late spring and
bloom all summer well into fall. Daffodils will pop up in late winter, early spring,
so they're never blooming at the same time. So, with my Texas lantana in the same spot as
my daffodil what will happen is as the daffodils start to fade my Texas lantana will be starting
to grow and it will completely cover up the leaves of the daffodils. Now you normally want
to leave those upright so that the daffodil bulb can draw nutrients and be fed and store up energy
so it can survive the summer and come back again next year. But I also don't want a whole bunch of
dying-out daffodil leaves all over my garden. The Texas lantana will hide it completely,
and then what I do in the late fall / early winter when i cut my lantana back - that's also
when I will clean up any daffodil leaves that are still remaining. By then, they're all brown but
it's easy to clean up. So here's a good companion with two plants that have completely
different time frames, blooming in different seasons. That's what we mean by seasonality.
Aesthetically is another way that you can companion plant and this would be
through a contrasting texture, or color, or size. An example of this would be hostas and ferns.
They both have the same requirements. They want protection from afternoon sun. They like to be in
the shade. They have the same water requirements, but with hosta you get these big bold leaves and
with the ferns you get this soft, feathery look, and so the two completely different looks. But,
they're plants that want to be in the same spot and want the same conditions ideally and so that's
a great companion. Now, if you wanted to add some color to the mix - because your hostas and your
ferns are always going to be some shade of green - you can throw some coral bells into the mix.
Those come in wonderful colors with some browns, caramels, some burgundies and purples and reds,
and again the coral bells want to be in the shade just like the hostas and the ferns. So,
this is a great group of companion plants for a shady spot. Now, many of you probably
have experience with companion planting but don't even know it. If you've ever done a
potted arrangement or a container garden using the "potted plant principle" wherein you use
a thriller, a filler, and a spiller. That's an example of companion planting. These are... in
this case these are all sun lovers right here and it's an example of grouping the plants together.
They have similar water needs. They have similar light needs, and so they'll work well together.
So, companion planting - grouping plants that benefit each other in some way. They can benefit
aesthetically, by contrasting complementary color, texture, or size, or by seasonality.
Or they can benefit scientifically. This could be chemically, biologically and or
biochemically. Now, the classic example of this is the three sisters. This is something
that the Native Americans taught to the European settlers when they first arrived in North America.
This is an interplanting of corn, pole beans, and squash. You plant these all together and they work
together for the benefit of all. The corn, well, the stocks provide support for the climbing beans
the beans provide corn with the nitrogen needed for optimal growth, because beans and peas both
fix nitrogen in the soil and corn is a heavy heavy feeder. It needs a lot of nitrogen so it can shoot
up nice and tall and produce the corn. The beans will also help camouflage the corn. Their leaves
will camouflage the corn and and thereby help deter the corn earworm moth. The squash provides
shade that inhibits weeds and helps retain soil moisture. It acts like a mulch in a sense. It's
going to provide so much shade that the weeds can't really take hold and it's going to help
the soil retain its moisture and therefore all three of these plants are going to benefit.
So, scientific companion planting would be a symbiotic relationship where all of them are going
to benefit because they're bringing something to the table that the others don't have or need.
Now, when it comes to literature on companion planting - if you want to do some additional
reading, the classic text that almost every gardener i know has on their shelf
would be "Carrots Love Tomatoes" and then there's a sequel called "Roses Love Garlic." I believe
the same author has a third book out now but i'm not certain. "Carrots Love Tomatoes" dates back
to the early 90's, I believe. So, it's been around quite a while. If you're looking for
something a little more current, this one came out I believe in 2020 called "Great Garden Companions"
and the author is a Master Gardener, and that's got some great information in it as well. Now,
for me as a Certified Nursery Professional, our go-to book is the training manual that we all use.
It's a three ring binder about three inches thick and it's the material that we all have to know in
order to get certified, pass our exam. This thing has 680 pages and there's one page on companion
planting, and that's in chapter 8 on pest controls - Working with Nature to Control Pests.
Wherein we learn that, "Companion planting," which they define as, "an orderly mixing of crop plants,
is a cultural practice aimed at diversifying insect populations. Numerous claims have been made
about the ability of certain plants to protect certain other plants from insect damage. However,
no scientific data are available to prove the value of companion planting."
Now, that last sentence there is key. "...no scientific data are available to prove the value
of companion planting." Said another way, there is no peer-reviewed double-blind scientific study
proving the benefits of companion planting. Any proof of efficacy is almost entirely based upon
observational and anecdotal evidence. That said, there's a lot of observational and anecdotal
evidence. Returning to page 91 of the Texas Certified Nursery Professional Training Manual,
Third Edition, we learned that you should interplant tomatoes with basil to deter tomato
hornworms. Interplant cucumbers with radishes or nasturtiums to control cucumber beetles.
Interplant cabbages with thyme to control imported cabbage worms. Interplant potatoes with deadnettle
to repel the Colorado Potato Beetle, or interplant potatoes with horseradish to control potato bugs.
And just so you know, potato bugs and Colorado Potato Beetle are the exact same thing. And,
interplant roses with chives or marigolds to repel aphids. Now, some of my personal favorite
companions - especially for the vegetable garden, and by the way that is something you're going to
see when you go to these charts on the internet. A lot of it has to do with vegetables. I'm not
sure why that is, but that seems to be, I would say, 70% of the information out there
is regarding companion plantings and how different things help or hinder other vegetables.
So, some of my favorites -tomato and marigold. The marigold inhibits nematodes and it attracts
pollinators. I'm a big fan of planting annual color in my garden for my summer crops just as
a general general rule of thumb because I want to attract the pollinators. All of your summer
crops in North Texas - well, the vast majority of them anyway - have a flower. They're going to
flower and they will need some pollinators to help set the fruit, and having flowers
in your garden and your vegetable garden will certainly help that. Marigolds that will show
up on all these charts you're going to see as far as their ability to to inhibit nematodes.
Over the years I've had every problem you can have with a tomato plant. Nematodes have not been one
of them, but i've always planted marigolds with my tomatoes. Another combination is tomato and basil.
Now, basil likes a bit of shade. It doesn't want a full-on blast of sun like your tomatoes do,
so I like to plant my basil underneath my tomato plants because the tomatoes are going
to get nice and tall. I prune them pretty heavy so they're not going to crowd out the basil.
The basil also will help deter tomato hornworms, and of course, if you've ever grown tomatoes,
you know that hornworms are the bane of the tomato gardener's existence. Cucumber and nasturtium.
Now, these are both climbers. I always grow my cucumbers on a trellis, same with my nasturtiums.
The nasturtiums will help repel the cucumber beetles. They're both going to climb. They're
both edible. The flowers and the leaves the nasturtiums are edible. They have a very peppery,
spicy flavor to them, which kind of provides a nice contrast to the watery sweetness of a
cucumber. So, having them grow right there side by side is great. I harvest them at the same time.
I can put them in salads at the same time. Works out really well. And I love the colors of the
nasturtiums. So, that's that's another good one that I highly recommend. Now,
there are some companion planting no-no's because some plants do not play well with others.
On the charts that you're going to find on the internet these are often referred to as
"foes" in companion plantings. A lot of your charts will have "friends" and "foes" and the
"foes" are plants that inhibit the growth of their neighbors in some way. How? Well, aesthetically
they can crowd out their neighbors, and the primary culprit on this list would be mint,
which you don't want to plant anywhere that you don't want it everywhere. Another no-no would be
Greg's Blue Mistflower, which can take over a flower bed very quickly. Beautiful flower. It's
great for pollinators, butterflies especially, but I wouldn't want to put it in my vegetable garden.
You could also have a no-no on a scientific basis. Now, this would be either because of biochemically
or allelopathy - and that's a mouthful isn't it? Allelopathy is, "a biological phenomenon by which
an organism produces one or more biochemicals that influence the germination growth survival and or
reproduction of other organisms." A classic example of this would be Black Walnut versus
pretty much everything. Black Walnut produces a toxin called juglone that inhibits the growth
of other plants, and I know this from personal experience. My brother lives in East Texas. He
has a very mature black walnut tree in his front yard and his landscaping has never looked good.
And it's to the point now where he can barely get grass to grow, and even most weeds find it hard.
So again, that's a classic example of allelopathy right there. Another no-no would be peas versus
garlic and onions. Peas fix nitrogen in the soil and garlic and onions, being bulb type plants,
they don't need or want excess nitrogen. What they want is phosphorus. So these are often not good
companions. Potatoes versus tomatoes. Both are susceptible to some of the same diseases and pests
and, in fact, it's never a good idea to plant potatoes in the exact same spot in your garden
every year for more than three years. Same with tomatoes.
Likewise, you don't want to follow - if you're going to do a crop rotation - you don't want to
follow potatoes with tomatoes or vice versa. It's just not going to give you a good crop either way,
so you want to keep those two away from each other in your garden. Another no-no is cucurbits.
That would be...I would encourage you not to plant all your cucumber, squash, and watermelon in the
same spot of your garden. Or, like I did one year when I had a long, thin raised bed and I thought,
"Well, I'll put a trellis here and grow all of these." I had cucumbers, cantaloupes,
watermelon, and some squash at the end. All of these in the same exact bed and I thought, "Well,
this is great. You know. They're all going to grow up the trellis, or most of them are going to grow
up the trellis. This will be really easy." And that was the year that I learned about the squash
vine borer moth, which looks like a nasty red wasp, but it's actually a moth. It's going to
lay an egg - a lot of them - on the underside of the leaves. When that thing hatches, it's going
to crawl down to where the stem meets the soil. It's going to burrow inside and then eat the plant
from the inside out. And it loves cucurbits! And if it sees one, it's going to lay its eggs
there and they will just work their way right down the row and eat every single plant, which
is what happened to me. So, that's a great reason there not to plant all your cucurbits in one spot.
In conclusion, companion planting is worth your time and effort. It's a lot of interesting
information out there. Again, some of this anecdotal evidence, this observational evidence,
has been passed down for generations and generations. Some of this is hundreds or thousands
of years old, so there has to be something to it. And in my own gardening experience I've
seen that it does work. If you're looking for some additional resources, I highly recommend
this little publication right here. This is from the Galveston County Master Gardeners,
their April/May 2014 issue. It's a pdf that you can download and there's about four to six pages
about companion planting. Most of the issue is dedicated to that,
and you can download this. Another great resource, the Farmer's Almanac. They have a planting guide.
Mother Earth News. Again, there's tons of these out there, but these are the ones that I found
the most helpful when I was putting together this presentation. The Old Farmer's Almanac.
They've actually got two, one specifically for vegetables and another where it's more generic.
The Spruce is a great website. If you've never spent time there, they have a good one. Good
Housekeeping, and of course, Burpee, the seed company. Don't worry about trying to pause and
write all these down. I'm going to put the links below, so you'll have access to them. So, there
you go. Hopefully you now know a little bit more about companion planting. I'll leave all those
links in the description below, and if you'd like more information about the Frisco Garden Club you
can find them online at friscogardenclub.org. I'm Tim and this has been the Shades of Green Show.