Beating the heat: Hoyas’ coronas, corollas and peduncles

18 year old Cattleya - a division from an orchid that belonged to my mother

The husband and I are enjoying a few peaceful evenings, our last for a while. The grandchildren and their dog are arriving on Thursday, and life as we know is about to end. We will be spending time in the pool, going to the movies, making S’mores, camping and anything else we can think of to keep them busy!

While time in the pool will keep us cool, it’s important to practice safe gardening techniques when spending time doing chores in the garden. Limit time in the sun by working in the early morning or late in the evening. Avoid the 10 a.m. to 2 p.m. time period when the sun is at its strongest. If you must do garden chores in the middle of the day, be sure to work in the shade and use sunscreen. Protect your skin by wearing loose clothing with long sleeves and head gear. Drink plenty of water to stay hydrated and take frequent breaks to reduce the possibility of heat stress.

After all that hard, sweaty work in the garden, time to go inside and enjoy the cool air, a nice bath and iced drink. Unfortunately our hot, dry weather can have unintended consequences as far as the air conditioner is concerned. To ensure that cool air continues to provide you with uninterrupted relief be sure to change your air filters. Dirty filters block normal air flow and can up your air conditioner’s energy consumption by 5 to 15 percent.

Check your evaporator coil and condenser coil and clean if necessary. Outdoor condenser coils tend to become very dirty in dry weather. Make sure the area around the coil is clear of leaves and other debris. Trim shrubbery near the unit to ensure adequate air flow around the condenser. Don’t forget to check for clogged drain channels because this can be a problem and prevent a unit from reducing humidity.

When you slip out to the garden in the early morning to add plants that will stand up to this heat consider succulents!  The best way to deal with heat is to fill containers and hanging baskets with succulents. They thrive in high heat and humidity. If you forget to water for a few days, your containers will still be attractive.

One of my favorites to use in hanging baskets is members of the Hoya family. In nature, Hoyas cling to trees by aerial roots. There are more than 200 members of the Hoya family. Mostly vining, tropical plants are native to southern Asia, Polynesia and Australia. Some originate from the subtropical foothills of the Himalayas and can take temperatures as cool as 45 degrees.

Commonly called the wax plant, Hoyas have thick, smooth leaves which appear in a range of sizes and colors. The vast majority of Hoyas has succulent or semi-succulent leaf tissue and is drought-tolerant. The leaves can be variegated in shades of silver, white, pink or red, on leaves that are dark or light green. The leaves can be glossy, fuzzy or heavily veined.

Each flower has a five-part corona on top of a five-part corolla. Some are fringed while others are smooth and waxy. The flowers originate from peduncles or bloom spurs. Most Hoyas rebloom on existing peduncles, so be sure to leave them in place after the flowers have dropped. Peduncles grow with each round of bloom.

Hoyas belong to the Asclepiadacea, or milkweed, family. Hoya seed ripen in pods and float on silk just like other milkweeds. They aren’t viable for long, and most Hoyas are propagated from cuttings. Dip cuttings in rooting hormone and place them in a lightweight mix. They should root within six weeks.

During the warm growing season, plants should be watered once a week and given a balanced fertilizer every other week. Never allow Hoyas to sit in water or persistently damp soil. They are epiphytic semi-succulents – wet roots can be deadly.

Some great examples are H. carnosa, which has light pink blooms, and H. kerrii, known as the sweetheart Hoya because of its large heart-shaped, variegated leaves and red and white flowers. If you like to play cards, then H. curtisii is for you with its spade-shaped leaves and flowers flecked with silver and red. Each flower is almost as large as the leaves. H. lobbii is a reliable addition to your garden and as a house plant. The maroon coronas crown dusky pink corollas; the flower can last for two weeks. Others to consider are: H. caudata with its prominent stamens and fringed petals, H. lacunose that is highly fragrant and H. vitellina that has medium green leaves that are edged in purple.

This is a tiny sampling of a fascinating family of vines that will bring pizazz to summertime containers and hanging baskets. They are a lot like the proverbial potato chip – can’t stop at one!

Another great addition to the garden and containers is the Sansevieria, a genus of approximately 60 species native to Africa, Madagascar, India and Indonesia. This family of plants is versatile – thriving in deep shade to partial sun.

Sansevierias were introduced to Europeans in the early 19th century. They gained popularity as houseplants, becoming a fixture in Victorian English parlors to the villa patios of the Mediterranean. They regained favor with the advent of modernism in the mid-20th-century. Their sculptural appearance was a perfect match to the minimalist style of contemporary architecture. It has been said that their combination of utility and sleek stylishness makes them the botanical equivalent of the little black dress. Who doesn’t appreciate the little black dress!

Ease of culture makes them an ideal plant for the beginning gardener. After all, it’s almost impossible to kill them, and beginning gardeners need a successful experience with plants to foster the love of gardening.

The only sure way to kill a sansevieria is overwatering – these plants evolved in hot, dry locations. Protect them from excessive winter moisture. Their low water needs make them the right plant for our droughty conditions. Mealybugs and spider mites can be a problem along with vine weevil grubs.  

They may be divided in spring. Propagate in spring or autumn by taking leaf section. Offspring from variegated cultivars will lack variegation if raised from leaf cuttings.

They come in many shapes and sizes. Some exceptional varieties to use in containers, hanging baskets and garden include ‘Hahnii’ better known as bird’s-nest and S. cylindrical, the spear sanservieria. S. trifurcate, snake plant or mother-in-law’s tongue is the most common. Had to be a man that gave it its common name! It is the original brown-thumb houseplant and will tolerate neglect. If you kill this plant you should find another hobby! ‘Laurentii’, gold band, is similar to the species. I have a gray variety that I haven’t identified but love the way it looks in containers and the shade garden.

There are so many other succulents that are perfect for containers and hanging baskets. The different shapes and colors of succulents can be used to design an ocean reef, water lilies and a multitude of other looks. The next column will cover more of these remarkable plants. So addictive – hard not to want them all for the garden!

Happy gardening.

Texas Master Gardener Columnist: Down the Garden Path