Growing flowers in zone 9b means that we have to have a robust handle on the summer loving flowers that grow well in our area. We are so blessed with such an extensive growing season. While spring time can be unpredictable in our area, because our spring really doesn’t have true spring attributes, summer is a lot more predictable. We know it's going to be HOT, hotter and miserably hot. Having a well rounded list of flowers that thrive in the sunny summer months set us up for a season of success.
Sunflowers- these are more like weeds than flowers they are so easy to grow. They thrive in the heat! We grow specific varieties that are best for cut flowers- specifically the Pro-Cut series. These are a “one hit wonder” meaning each seed/plant only provides one flower. This is best for growing cut flowers. There are also branching varieties of sunflowers that give you about 5-8 flowers per plant. Sunflowers do best being direct seeded, if planted in cell trays they will quickly outgrow their cell and start stretching for the sunlight so, plant them quickly after. We use a walk-behind seeder that buries them in the ground about 6 inches apart. For flowers all summer long we succession plants every 1-2 weeks.
Dahlias- You cannot go wrong with dahlias! These amazing cut and come again flowers are so hearty and resilient in our hot climate. These flowers grow from tubers, resembling a cluster of sweet potatoes. The best part about them is they come back year after year and while they are producing gorgeous cut flowers they are also producing more tubers under the soil that you can dig up in the fall and divide to get more plants! They do best with well draining soil and consistent water. Installing drip irrigation is better than hand watering! Dahlias come in all shapes in sizes and in every color under the rainbow. They are my favorite summer flowers! These flowers benefit from pinching as well.
Zinnias- these heat loving flowers are the key to every good summer cutting garden. They are a “cut and come again” meaning the more you cut them the more they produce. Proper harvesting stage for them is when their stem is firm. We use what’s called the wiggle test, we make a peace sign with your hand and stick the stem in between your fingers and move the stem back and forth and if the head is floppy it's not ready to be harvested. The most common cut flower varieties that we love are the “Benary Giants” but the “Queen Lime” series is a must have also. We succession plant them throughout the summer but we try and put in a new planting about every 6 weeks. These flowers benefit from pinching as well.
Celosia- My moms favorite summertime staple. They come in a variety of colors, shapes, and forms. We personally LOVE the “Chief” series, these are the cool ones that look like fuzzy brains. “Chief Gold” (pictured below) is probably our favorite. There are also plume celosia, this one is great as well and can be used as a spike element in arrangements. Celosia thrives in hot and dry conditions and lasts forever as fresh flowers but can be hung upside down to dry. Putting them upside down in a paper bag will dry out the flower head and the seeds will drop, you can then use them to grow in your garden the next year.
Cosmos- I really have a love hate relationship with cosmos. They would be perfect for a home gardener but since we grow so many of them they become VERY time consuming to harvest. Because multiple flowers bloom on one stem there is normally one or two flowers that are past their prime point of harvest so its even more time consuming to comb through them and cut off the bad ones. But they add a whimsical and airy element to bouquets which I love. They are a cut and come again flower so the more you harvest the more they will produce. We grow the “Double Click” series simply because we like the look of them better than the single varieties. The single ones are great but the doubles are just ruffly and hard to resist. Cosmos give longer stems and more flowers per plant when pinched!
Amaranth- This flower screams fall to me, but it thrives in the heat and can be grown all summer long. Amaranthus comes in a few beautiful colors- Autumn Touch, Red Spike, and Hot Biscuits. These varieties are specifically upright, there are also hanging amaranthus but we don't grow those, not because they aren't beautiful just because they are harder to use in wrapped arrangements. These are a great spike/filler flower in arrangements and give a beautiful seedy texture. These flowers benefit from pinching- by cutting out the center stem it will promote side growth that is much more usable in bouquets. If it's not pinched it will produce one huge broomstick size flower which is really hard to arrange and has a hard time hydrating itself because of its large stem!
Lisianthus- I've saved the best for last! Lisianthus are slowly getting more and more planting space at our farm every year. Not only do they come in a wide variety of colors but they have an incredible vase life- ranging from 10-14 days. They start to bloom around mid June- early July if planted in February-March. They are very slow growers, so we do not start ours from seed, we buy ours as plant plugs. Making sure they are in well draining soil and their area is weed free will give them long, branching, and strong stems. My favorites are the “Voyage” series because they are super ruffly. You can’t go wrong with any variety but I just prefer the ruffles! Lisianthus will come back for a second flush about 6 weeks after you harvest the first blooms- make sure to cut above a set of leaves, if you cut it down to the ground and don't leave any leaves it will not come back for a second flush . Don’t harvest your lisianthus when the first flower blooms- it is so tempting but wait til that first flower dies and the other buds start to burst before cutting.
I hope this guide is helpful in choosing some staple heat loving flowers that thrive in our warm climate! We grow all these varieties at our farm and love every single one of them.