Although August is my favorite month, its reputation for being hot, humid and sticky is well-deserved, this year included.

What a relief, then, when September arrives. Clear blue skies, warm temperatures and cooler nights, and the summer flowers keep blooming right along with their fall companions.

If petunias are one of your favorite flowers, take the time, if you can, to check out the steps leading to the University of Iowa main library. Each of the four supports for the steps is covered with a profusion of petunias. It is simply beautiful.

It was such a pleasant surprise when I saw these climbing and spreading petunias. Kudos to the university’s landscaping department for their choices of colors and cultivars, and for the design.

One of September’s special offerings is the Sweet Autumn Clematis just beginning now to be covered in tiny, pure white flowers. You will see them draping over fences or being the centerpiece in a garden.

And you will see them aggressively pushing out other plants that get in their way. Sweet Autumn is a creeper, a climber, and somewhat of a bully.

In my small garden, my clematis is a nemesis. It has tangled with the tomato plants in the garden behind and shaded the neighboring squash, and taken over my morning glories.

Last month, I did the unthinkable and pruned it. It is to be pruned only after it blooms or early in the spring. But since it seemed not to know its boundaries, I needed to cut away as much as possible. 

It is blooming now and doing quite well considering how I treated it.  It is still a favorite, a beautiful fall bush.

Dahlias are one of the best fall flowers. They grow from a bulb planted in the spring. The bulbs are called tubers and look like a bunch of brown carrots. And from these can come the most beautiful, colorful flowers, some as large as a dinner plate.

You should wait until after the last frost in the spring to plant dahlias. Plant them when you plant your tomatoes. The soil should be around 60 degrees.

Since it is a waiting game, do mulch where you plant them. A thin layer, about 1-2 inches, will absorb moisture and keep the temps even.

When you plant, use a surface fertilizer. However, dahlias love coffee grounds. Sprinkle them around the plant for an extra dose of nitrogen, potassium and phosphorus.

Dahlias come in bright red, deep fuschia, and other strong colors. There are many different shapes and sizes of dahlia blooms. Some are quite small, or have sharply pointed petals, or tightly closed petals, or are bicolor.

Remember all need to be dug up in the fall, Hose the dirt off and let dry, then arrange so they do not touch each other, and store at about 40 degrees.

To divide them and to be sure you are preparing them properly, I would suggest a book or video that goes into more depth than I can in this column. I do know with good care they last for years. Once I visited a garden of all dahlias and one had been going since 1903.

Right now the Black-eyed Susans are giving such great color, as are sunflowers. A sunflower called Mexican Hat is bright orange and is a nice change from the yellow.

The common sunflower may grow to over 10 feet. The tallest ever recorded is 30 feet.

By next week it will be officially autumn. As the leaves change, summer flowers decline. But autumn flowers, such as the dahlias, sweet clematis, sunflowers and the ever-hardy mums, make fall a special, colorful season.

Note: It is spring bulb time, too. Daffodils are great because the deer do not like them.  They love tulips. But I think I will plant a few tulips and hope for the best.