When To and When NOT to Plant Flowering Annuals

home improvement store
Flowering Annuals

Each year, around the end of August, I walk into the plant section of our local home improvement store just to look at the colorful, flowering annuals

While I may be sorely tempted,  I don’t buy any; I just like to look.

BUT, I know that I am in trouble when the majority of the nursery shelves is covered in a sea of winter annuals – I feel like a kid in a candy store.  The vibrant colors and scents are almost intoxicating – to me anyway.

In the past, when I managed landscapes on golf courses, I would come to the store in our work truck and load countless flats of annuals for planting around the golf courses and the other buildings.  I loved planning ahead of time what I would plant and the color combinations that I would use.

Flowering Annuals

  Petunias, bacopa, and alyssum

In the low desert, winter annuals typically show up in the nurseries around late August, and it is so easy to get caught up in the excitement of fall being just around the corner along with the promise of cooler weather.  So before you know it, you buy a bunch of flowers and run home and plant them.  The problem is, is that it is often still too hot for them to survive.

Flowering Annuals

  Red geraniums with bacopa

For years, I would tear out the summer annuals around the golf courses and plant winter flowers in late September, usually with good results.  Of course, I would have to be vigilant and replace a few plants that would fall victim to the warm September temperatures, but overall they did fine.  

That is until one year when we had higher than usual temperatures in early October.  The flowers kept dying despite my best efforts.  Each day on my way to work, I would have to stop by the nursery to buy replacement plants.  This got kind of old after 2 – 3 weeks and I would have to go from store to store to find the same kind of flowers that I needed.

Flowering Annuals

 Blue Petunias 

So, I learned my lesson – no matter what, we would not plant winter annuals until late October.  I mean, it was silly to pull out the summer annuals in September when they still looked great.  I think people want to get a jump start on winter flowers because it makes us feel like the weather is cooler when it isn’t.  So unless you want to make extra visits to your local nursery, WAIT until mid-October.

Now, since I no longer manage landscape areas, I am only responsible for my annual pots.  Last year I planted hot pink geraniums with alyssum, and they did very well.  In the past, I have tried the following combinations with good results:

– Yellow Snapdragons with Blue (Deep Purple) 

– Petunias and White Alyssum

– Red Geraniums with White Alyssum

– Hot Pink Geraniums with Lobelia

– Yellow Pansies with Lobelia 

– Light Blue Pansies and Alyssum

– White Snapdragons with Pink Petunias and Lobelia 



PLANTING:For containers (pots), I use a planting/potting mix, which is specially formulated for containers – not potting soil, which can become soggy.  

If you are planting annuals in the ground, then I add compost or potting soil to the existing soil at a ratio of about 1 part compost to 1 part existing soil.  

If you do not have a compost pile at home, you can buy bagged compost at your local nursery.  Add slow-release fertilizer, following directions on the label.  Plant your winter annuals, making sure that they have enough space between them to grow.

CARE:  Water twice a day.  I usually water in the morning and maybe late in the afternoon as the plants are becoming established (about two weeks).  You can then water once a day or every 2 – 3 days, depending on the weather.  

In a managed landscape setting, I would also fertilize weekly with a liquid fertilizer to promote maximum blooming.  At home, I usually fertilize every other week.



Now that we are in the second half of October, I am ready for planting winter annuals in my garden.  I have been thinking about planting violas.  I have not planted them since I was a little girl and I did notice some beautiful ones at the nursery back in August.  Those violas are probably dead from the heat of late August.  

Hopefully, they will have some new ones in now that it is really time to plant!

A Children’s Flower Garden in a Kiddie Swimming Pool

Noelle Johnson, aka, 'AZ Plant Lady' is a author, horticulturist, and landscape consultant who helps people learn how to create, grow, and maintain beautiful desert gardens that thrive in a hot, dry climate. She does this through her consulting services, her online class Desert Gardening 101, and her monthly membership club, Through the Garden Gate. As she likes to tell desert-dwellers, "Gardening in the desert isn't hard, but it is different."
24 replies
  1. Amy
    Amy says:

    I was just getting ready to look up the soil mixture I should start using for my plants. Thanks for answering my question! Your posts are informative and I love the pretty combinations.

  2. Carol
    Carol says:

    I have to laugh at the contrast … as we are tearing out frost bitten annuals you are beginning to plant them. I am not envious just yet as our fall is still lovely but soon when winters coat of white is all about I may begin to feel a bit jealous of your climate. I love the hot pink with the shrub in the back… so daring! Many lovely combinations. Enjoy your cooler weather. Carol

  3. Nell Jean
    Nell Jean says:

    When I first moved to south GA, the plant ladies in the next county planted White snaps, Iceland poppies in citrus shades and blue pansies in front of the Vet's office. Prettiest display I ever saw.

    Your combinations all sound just marvelously pretty.

    I have to stay away from the nursery until November so as to plant violas (my fav) after the hottest days are over for sure and a new supply comes in. I can hardly wait.

  4. Hortist
    Hortist says:

    Hellow Catherine, it's nice to read that you are a Landscape Horticulturist by profession. I'm also a Landscape Horticulturist but still in the primary phase of my career. Really nice to meet you….your combinations for annuals are really attractive, I appreciate them all…..nice day 🙂

  5. Muhammad khabbab
    Muhammad khabbab says:

    I agree when a gardener sees so many flowering plants feels like a kid in a candy store.I also bought a seedling of dahlia and phlox last day although i had no intention at all. As phlox has started flowering, so time for winter flowers has just started.

  6. Janet
    Janet says:

    It is certainly interesting to see the contrast of seasons across the country. Your desert garden is most interesting to hear about.

  7. Rosey Pollen
    Rosey Pollen says:

    The blue petunias in that photo are a huge pop of color! Love it!
    I love violas. They are pretty hard so they are welcome in my garden anyday. Thanks for the tips on the planting medium, I always forget to add compost to the potting soil.

  8. Yan
    Yan says:

    Like Carol, I find it funny we plant the same annuals, but in opposite seasons. Petunias, lobelia and geraniums mean Summer heat here. Violas are lovely and repay the smallest amount of work with long lasting displays. I had two tubs of a lovely delicate viola this summer, the flowers of which were almost white when they first opened and then slowly darkened through sky blues to deep violet. Planted them as seeds in Feb and they are still flowering. Go for it.

  9. Flowers
    Flowers says:

    What an incredible blossom viola is. I am not at all familiar with this plant, but it sounds like one I would like to get to know better.

  10. CCAZJeff
    CCAZJeff says:

    I was once told by of U of A professor to avoid mixes made with peat/peat moss because if they dry out they are very hard to re-wet.

    It is difficult to find a prepared soil mix without peat moss in it.

    What is your take on this issue?

    Thanks – [ Jeff ]

  11. arizonaplantlady@gmail.com
    arizonaplantlady@gmail.com says:

    Hello Jeff,

    To be honest, I have not had a problem with the soil drying out. I do avoid using large amounts of peat moss because of it tendency to create an impervious layer against water. I do make sure that the soil is moistened before planting. I am careful to keep the soil from drying out. If this does happen, I would slowly water the area so that the water permeates down into the soil. You can also poke small holes about 6 – 8 inches deep with the end of a wooden spoon or a piece of rebar, which should help the water get down to where it needs to be (be careful of the roots). You might also try water retaining gel which is mixed into the soil and releases water as the soil dries. I hope these help.

  12. Mary Delle
    Mary Delle says:

    I love your suggestions for plant combinations for winter. I'm also waiting until the heat abates. We're supposed to have another Santa Anna at the end of the week.

  13. Jan
    Jan says:

    I, too, have learned the hard way to wait until November 1st to start planting the winter annuals, esp. pansies.

    Always Growing

  14. Kanak Hagjer
    Kanak Hagjer says:

    Your combinations are a visual treat and I think your post has answered many questions. I found it very interesting and although I've been planting in pots for so long, it's always good to read about the right kind of soil mixture. Our winter planting time is now, so there are many points I could relate to. Thanks.

  15. Msrobin
    Msrobin says:

    We have the opposite problem here in the midwest. The pretty summer annuals are out at the garden centers in April, but we know darn well that there will be another freeze, so we need to hold out till mid May when it's "safe"! I sure wish we could plant flowers in winter, but no such luck. That's why I hate winter so much!

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