How to Grow and Overwinter Popular Patio Tropicals
How to Grow and Overwinter Popular Patio Tropicals
Container gardening has become increasingly popular in recent years because it can be done in even the smallest spaces. Gardeners everywhere are expressing themselves with colour and an ever expanding range of plants, including tropicals!
Hibiscus & Oleander
- Hibiscus is available in single or double flowers in a range of stunning colours from red, pink, burgundy, yellow, peach and white.
- Hibiscus is also available in a bush form, tree form with single, spiral or braided trunk.
- Flowers last one day but the plant is prolific if given proper cultural care.
- Hibiscus makes an ideal houseplant.
- Oleander (Nerium) also comes as a bush or tree form and grows vigorously.
- Flowers occur in clusters in pure white, peach or pink.
- The pink flowers have a spicy fragrance. Leaves are leathery and willow-like. The wood and sap are both poisonous.
Brugmansia & Datura
Brugmansia or “Angel’s Trumpet”
- Brugmansia is woody and has pendulous (not erect) flowers that look like huge flared trumpets, hence the nickname.
- It’s most often over-wintered inside as a tree.
- Datura is generally grown as an annual and its trumpet-shaped blooms are erect or spreading, never pendulous.
- Spiny round fruit split open to release numerous seeds that can be kept and sown the following year or left on the ground to germinate naturally next spring.
- All parts of Brugmansia and Datura are highly toxic.
South African Mallow, Princess Flower, Royal Robe and Flowering Maple
These 4 patio tropicals are most frequently grown as small standard trees in full sun.
• South African or Cape Mallow is covered almost continuously with small, pale pink, hibiscus-like flowers.
• Princess flower (Tibouchina) has dark green, velvety, 10-15 cm (4-6″) long leaves with several prominent longitudinal veins. Large royal purple blossoms, flaring open to 12 cm (5″), are held above the foliage creating a spectacular sight when in full bloom.
• Royal Robe (Solanum rantonnetii) has profuse, saucer shaped, dark purplish-blue flowers about 2.5 cm (1″) wide. It tolerates heat and humidity well.
• Flowering Maple (Abutilon) is not part of the Maple tree family. The common name is derived from its attractive maple-shaped leaves. Some varieties have brightly splashed variegated leaves. Flowers are cup-shaped with 5 overlapping petals in red, pink, yellow, white or pastel shades.
Exotic Flowering Vines
Mandevilla, Passion flower and Bougainvillea are excellent candidates to be trained on some kind of vertical support in a container.
• Mandevilla (Dipladenia) has shiny, heavily textured leaves and pink or white trumpet-shaped flowers that can be 7.5 cm (3″) across. Twining woody stems make this a rampant grower as well.
• Passion flower which grows really quickly in full sun also looks sensational covering an arbour. The blooms of this tropical vine are incredibly intricate and come in red, blue, mauve and pink. The fruit is also edible.
• Bougainvillea produces long, arching, thorny branches. The flowers look like delicate paper but are, in fact, bracts. The true flower is small and white inside the outer showy bracts that can be brilliant pink, purple, lavender, peach, orange or white. Some varieties have interesting variegated foliage. Given lots of sunlight, Bougainvillea blooms all summer long.
How to Grow Patio Tropicals
All of these plants originate from hot, sunny, southern climates, so they’re used to intense light levels. They flourish in morning light that lasts until 1 or 2 in the afternoon.
Keep soil moist during their blooming period or, in the case of Hibiscus, water the plant when it just starts to wilt. Too much or too little water for patio tropicals will result in foliage turning bright yellow and dropping. The combination of sunlight and regular fertilizing will ensure continuous bloom.
Fertilize every 1-2 weeks with water soluble 15-30-15 or apply Hanging Basket Food 14-14-14. These controlled release granules, applied to the soil surface, feed plants for 6 months with just one application.
Over-wintering Patio Tropicals
- Bring your patio tropicals inside around late September before night temperatures get really cool.
- Prune plants that put on a lot of growth in previous months.
- Spray several times for insects with an insecticidal soap or Safer’s End-All.
- Be sure to treat the soil with Wilson Fungus Gnat Spray. Hibiscus, Abutilon, Brugmansia and Datura are prone to whitefly. They require radical control to prevent clouds of these insects in your home. Because eggs are deposited on the underside of leaves, you need to remove all foliage before bringing indoors. You’ll be truly amazed to see healthy new growth within 3 weeks and the plant should remain insect-free all winter. Remember to monitor carefully all your other plants for insects so they don’t infest the patio tropical.
- Light levels in the northern hemisphere are very low December-March. During this time patio tropicals take a rest. Unless you have a particularly bright sunroom or conservatory chances are plants won’t continue to flower and you may experience significant leaf drop. This is especially true with Bougainvillea.
- Water your plants less through the winter months, stop fertilizing and keep them in a cooler room.
- In March, you can water more frequently and fertilize again.
- When all risk of frost has passed, bring plants back outdoors but place them in shade to start. Direct sun at the start of the season scorches leaves.
- Thriving plants will soon outgrow the pots they’re in and can be transplanted into containers 2.5-5 cm (1-2″) larger than the ones they’re presently in.
- When you’ve reached the maximum size and can go no larger, you need to lift the entire root ball out of the pot, prune the top of the plant and cut 2.5-5 cm (1-2″) off the sides and bottom of the root ball with a very sharp knife. Put fresh soil in the bottom of the existing container and center the trimmed root-ball in the pot, backfilling the sides. This will need to be done about every 2-3 years.