Ask Mr. Smarty Plants

Native cactus are a fascinating and sometimes challenging group of plants to grow. But the rewards are significant when their culture is mastered and they bloom profusely. You have picked very interesting cactus to grow in Dallas. Good luck with them.

Epithelantha micromeris (pingpong ball cactus) has often clumping, globose stems up to 1 inch in diameter (2.5 cm), occasionally more; small tubercles, 1 mm long; small areoles, slightly woolly when young; 20 or more white spines, 2 mm long, longer on the top. The Button Cactus has 0.2 inch long (5 mm), 0.16 inch wide (4 mm) pale pink flowers that appear in May-June at the apex of the plant. They only partly open, as they barely stick out above the wool an spines at the top of the plant. They are followed by thin red fruit, 0.3 to 0.5 inch long. This cactus grows best in full sun in well draining soil, but it will tolerate light shade.

Echinocactus texensis (horse crippler) The Horse crippler cactus is broader than it is long. Normally it is 1–2 inches above the ground and up to 12 inches across. It is difficult to see, and many horses have been crippled from stepping on it. It usually has only 1 stem, occasionally 2 or 3. If injured at the tip, it may produce a cluster of small heads on top of the old one. The surface of the plant is dark green. It has about 14 spines at each areole, with a central spine that is longer and stronger than the others, 2– 3 inches long and straight to slightly-curved downward. The inverted bell-shaped flowers are 1– 2 3/4 inches across and about as tall. The outer petals are salmon-red, the inner ones salmon-pink with streaks of red. The edge of the petals has a feathery appearance. Anthers are pinkish to red, and the pistil is yellow to pink. The flower is somewhat fragrant.

The TAMU Aggie Horticulture website has a good information page on growing cactus (and succulents) with information about how to care for them indoors. You have a good grasp of what is required to keep cactus (native or otherwise) alive indoors and that is diligent attention to the amount of water and light they receive. The worst situation is to overwater them.

Here's some of what is on the TAMU web page ... Cacti are a group of plants that are not only easy to grow, but offer a variety of shapes, color and form. They can be grown in any sunny, well-drained area. They require little maintenance. They make excellent houseplants and many hardy varieties may be grown outside.

The quantity and frequency of watering provides one of the biggest dilemmas to cactus owners. Since a cactus does not wilt at the first sign of drought stress, the plant offers few cues that it needs water. A good rule of thumb is to water when the top 2 to 3 centimeters of soil is dry. This should be adjusted with the season.

However, as plants will require more water during the period of summertime growth than they will during the slowed, or halted growth of winter. In winter, the plants may require water only once a month. During winter, you should supply just enough moisture to prevent the roots from drying and dying. One of the most important considerations in watering a cactus is to never let the pots stand in water.