One way to make a hot summer more enjoyable is to plant lots of annual flowers that take the heat and keep on flowering. Many of these heat-tolerant annuals are commonly available starting about mid-May.
Rudbeckia ‘Indian Summer’
One group of plants, rudbeckia, or black-eyed Susans, has many great perennial varieties that are commonly planted, but you will also find a few incredible and showy annual varieties. The advantage of an annual over a perennial is that with the annual you will get a much longer bloom period, sometimes season-long, where most perennials bloom for only 3 weeks or less.
One such annual form is rudbeckia ‘Indian Summer.’ It has an intense flower display and is relatively easy to grow. Plant in full sun in good well-drained soil and this plant will take off. Keep plants fresh by removing spent flowers as they fade. In my garden this plant comes back from seed and is a welcome addition wherever it emerges.
Spiderflower & lantana
Another heat-tolerant annual that comes back from seed each year is cleome, or spiderflower. This tall annual typically grows 4 to 5 feet in height so give it room. Each flower of this plant seems to never end, blooming continually, elongating and growing taller and taller each day. The seed pods that remain behind as the flower grows upward look like tiny pea pods and extend off the stalk like spider legs, which is where it gets its name. A great tough annual for full sun, it is available in white, light pink, dark pink, and lavender. This tall annual also has tiny spines along the stalks so watch out.
It is impossible to talk about heat-tolerant annuals without mentioning lantana. This tropical plant is certainly not new to our area, but there always seem to be new colors to choose from. You can find lantana in hanging baskets, pots, or as topiaries to use in containers or the garden. The hotter it gets the better this plant seems to look, so if you have a hot spot where it seems no other annual will grow, give this one a try.
We have mentioned a few plants for the sun, but if you have a hot shady garden what can you plant? I tried Strobilanthes, or Persian shield, and grew it first in a container garden. I was thrilled and it received more comments than any other part of my garden that year. I find that it performs its best in an area that receives morning sun, but is shaded from the hottest afternoon sun. It is a great container garden plant but performs equally well when planted in the ground. Its unusual purple leaves turn silvery as they age, and it looks wonderful planted in combination with the chartreuse sweet potato vine.
When it becomes too hot to do anything but just sit and relax in the garden, I am always glad that in early June I planted a few tough, heat-tolerant annuals.