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Holla! Hoya!

24 May 2021
june hoya
Able to hang off shelves and climb up suitable supports, hoyas can also grow many metres long, which is something worth considering no matter where you put them.

Far from fusty, hoyas don’t ask for much – but they deliver in spades.

Words Sue Witteman

You could be forgiven for thinking hoyas are nana plants, but you would be so, so wrong. The humble Hoya is a hot must-have on everyone’s want list. Once you start appreciating these plants, the need to own more begins and soon you will find yourself on the hunt. Luckily there are many hoyas available, from the affordable to the (gulp) almost-not-affordable. So, let’s get to know the hoya clan.

First up, what do hoyas look like? Their evergreen leaves are usually leathery-looking and many have quite thick leaves, usually green in colour, but there are also some stunning speckled and variegated versions. They come in a range of shapes and sizes – thin, round, large, long, puckered, small, oval, twisted, heart-shaped – and some even have tiny hairs that give a downy appearance, such as Hoya serpens.

While hoyas are good-looking enough when they just have leaves, the excitement factor ramps up when the flowers appear. The flowers are delicate umbels of fragrant loveliness and, depending on the variety, can be white, cream, pale green, pale pink, rose or maroon. The flowers appear between late spring and early autumn.

At the more affordable and available end of the Hoya spectrum, you will find H. carnosa and H. bella.

Favourable conditions
When the days get warmer and the frost danger has passed, you can put your hoyas outside, preferably in dappled shade. This summer I hung my hoyas underneath an outdoor umbrella (using the handy ribs to hook them on) and they loved it so much that I shall repeat this again next summer.
If you do need to grow them inside in summer, don’t place them in a hot north-facing window – most hoyas grow as epiphytes under the canopies of trees and as such don’t appreciate being cooked. Do, however, provide lots of bright, indirect or diffused light or grow them in an east-facing window where the light isn’t as harsh. They are also fond of humidity, especially H. bella – she likes it warmer and moister than many other hoyas.

If your hoyas have sojourned outside in summer, move them back inside come winter (unless you are frost-free or have a glasshouse) and give them a spot that is bright and airy.

At this darker time of year, ensure your hoya gets lots of bright light – this is necessary to initiate flowering later on. However, do not keep your hoyas too warm (they like a rest period during winter) as this can cause them to grow lanky and become prone to pests. When they come back into growth at the end of winter, move them slowly back to a warmer spot. Hoyas like air movement but not cold drafts, so place them accordingly.

How to grow hoyas
Hoyas must be planted in a free-draining mix. You can use a simple cacti and succulent mix or get fancy and add in some pumice or perlite, and orchid bark or coco coir (made from coconut shells). A rule of thumb for your overall mix is a third cacti or potting mix, a third pumice or perlite, and a third orchid bark or coco coir. This makes up a good epiphytic mix.
When it comes to watering, think more ‘succulent’ than ‘tropical’ plant. Let them dry out a bit between waterings as they do better if you keep them on the dry side. And, of course, never let them sit in water. Leaf drop can occur if your hoya has been over-watered or is too cold. Cut back on the water in winter – keep them barely moist.

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H. carnosa ‘Krinkle 8’ has leaves that look a bit like a snowpea.

Some people never feed their hoyas, but that seems a bit mean. Optimally, feed during the growing and flowering period (spring to early autumn), stopping when the flowering is finishing. Use a liquid fertiliser every two to four weeks when your plant is in full-on growth mode. If your plant is a shy flowerer and you haven’t been inadvertently cutting off the flowering spurs, then a fertiliser high in potash may encourage more flowers.

If you need to reduce the size of your hoya, cut it back in late winter but beware of losing the flowering spurs. If you need to repot, do this in August/September when the new growth is about to start. Avoid going into a pot that is too large – go up only one size bigger.

Occasionally, you may notice your hoya has yellowing leaves. This can occur if your plant is old, or it may indicate a nitrogen deficiency. Feeding should remedy this.

On display
Most hoyas can either hang or climb. If you want them to climb, a support or frame will be needed. They can be grown around a metal circle or cone or up a moss pole or trellis, or you can free-range them and let them climb around the room, attaching them with hooks, Blu-Tack or similar. A happy Hoya can grow metres, so factor this in when planning how to manage it.
It is interesting to note that you will get more flowers on stems that have been trained horizontally. Plus the older the plant, the more flowers it produces – it just gets better and better with time.

Pests or diseases?
Mealybugs, to my mind, are the worst and most frequent pests for hoyas. Why on earth mealybugs like sucking on the leathery leaves I don’t know, but suck they do. Hard to eradicate because of the nooks and crannies on the plant, and particularly tricky on the twisted leaves of the ‘Hindu rope’ types, I use isopropyl alcohol with water at a 70/30 dilution. Do this frequently – and don’t forget to look under the rim of the pot, where they often lurk.

Scale can also put in an appearance, as can mildew. Treat these issues as soon as you see them by improving the growing environment and spraying.

How to propagate
Hoyas are surprisingly easy to propagate. Take cuttings from November to January, taking young shoots that are starting to go woody at the base. The cuttings can be placed in water, leca (clay aggregate balls), a gritty or pumice potting mix, or sphagnum, and then put in a humid environment.
When taking the cutting, cut 1–2cm below a node, or even halfway between two nodes. The stem will produce lots of roots along the stem. Just one pair of leaves and a node is all that is needed for success.

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A rooted hoya cutting ready to be planted up.

Helpful things to know
Do not move or turn a plant that has formed flowering buds as this may cause the buds to drop off. Placing your hoya in a spot that is too dark may also cause bud drop.

Do not deadhead your hoya after flowering as by doing so you may damage the spurs that are nestled at the base of the old flowers and that will produce next year’s flowers.
Do not be in a hurry to repot your hoya – they like to be snug in the pot and often look as though they are in a pot that is too small for them.
No pampering!

So, there you have hoyas. They are very collectible, and with their ability to live a long time they could become true family heirlooms, passed down through the generations – a nice thought.

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