Doritis pulcherrima

One of the most reliable orchids for late summer and fall blooms is Doritis pulcherrima. Even the smallest plants rarely fail to send up a spike each year.
This genus is closely related to Phalaenopsis and much hybridization between the two has been done over the years. The Doritis genes bring smaller plant size and a more erect flower spike to their progeny.
The natural species usually only has a leaf spread of 4-6 inches and several plants can grow comfortably together in a 4-inch pot.

They multiply by clumping so it's typical to see plants grouped together in a single pot. When they fill the pot it's time to divide them, giving each one its own space. I like to divide in the spring, giving the young plants all summer to get established and ready for the annual bloom.
Individual flowers are about 3/4 inch across, with petals strongly recurved back toward the stem. The blooms open a few at a time, progressing up the spike, which continues to elongate as new buds are produced. The flowering period easily lasts for 2-3 months, with the spikes often reaching 3 feet in height. In high light the spikes are mostly vertical, but in shade they tend to bend toward the light.

Doritis pulcherrima is a fairly cold-tolerant species and survives brief temperatures in the upper 20°F range if situated under dense trees or shrubs during cold snaps. It also tolerates higher light and drier conditions than its Phalaenopsis relatives.

Turnera ulmifolia

Turnera ulmifolia (TERN-er-uh  ul-miff-FOLE-lee-uh) is an ever-blooming shrub that thrives in subtropical gardens. The bright yellow flowers each last only a day, but new flowers are continuously produced. The plant grows about 3 feet tall in a single season and requires very little care. It is drought-tolerant and thrives in nearly all soil types. The dark green leaves are usually about 2-4 inches in length and the flowers are about 2 inches in diameter.

Turnera ulmifolia is sometimes called yellow alder, but it is not an alder so that is a poor choice for a common name. There's really no reason to call it anything other than Turnera. It is native to the Caribbean and is recommended for USDA Zones 9-11. A hard freeze may knock it back to ground level, but it will quickly recover when the weather warms. In colder locations it can be grown as an annual. The plant reseeds itself easily and you're likely to find seedlings coming up all around the garden. The seedlings are easily identified by the distinctive leaf, so they can be pulled, transplanted, or allowed to remain where they sprout, depending on your preference.

Although you may find seedlings coming up in random locations, they generally aren't prolific enough to become weedy. The flowers attract butterflies, especially Gulf Fritillaries and Sulphurs.