Care tips

HOYA CARE TIPS

Here are a few care tips that I have found to work well in my home growing conditions. Unfortunately, there is no one-size-fits-all way to grow hoya and what works well for me may not suit you and your conditions. Every enthusiast must find their own path through experience, but I hope these tips can shorten that process for you.

MONITOR YOUR PLANT

There are hundreds of hoya species which come from various climates of Asia. Therefore, it is difficult to give guidelines that apply to all of them, but some basic principles may be helpful. Before we start, I want you to know that it is important to monitor changes in your plant. The color and texture of the leaves, as well as changes in new growth, tell you if your plant is in need. Yellow leaves may indicate, for example, a lack of minerals or root rot. Dried new growth probably means you’ve let your hoya dry out too much. A growing medium that has remained wet for too long suggests that it is not airy enough. Oops! Keeping an eye on these changes can help you address issues before they become more dramatic.

GROWING MEDIUM

There are 2 things hoya don't like:

  • too dense growing media
  • standing water at the roots

The medium must be airy and water-permeable, but at the same time contain a water-retaining component. Hoya’s delicate roots don’t recover once they dry out.

Every enthusiast in the field has their own medium mix, which reflects their personal environment and watering habits. There are options from 100% soil to completely soil-free solutions. Soil-free substrates are, for example, expanded clay or Lechuza Pon substrates. If you are in the early stages of a hobby, I recommend trying different media. Below is the growing medium I have used, which I have found to work in my own growing environment.

Hoyafixation Hoya substrate:

  • fine pine bark (2-10mm)
  • perlite (2-6mm)
  • coconut humus
  • potting soil formulated for houseplants
  • expanded clay
  • horticultural charcoal/biochar (5-10mm)

The substrate is airy and permeable to water, but at the same time retains moisture appropriately. After watering, the water initially drains onto the saucer, but is absorbed back in a couple of hours. Any water left on the saucer at that point is discarded. I use this growing medium for all my Hoya and leaf cacti or tradescantias, for example.

Sourcing growing medium ingredients might feel like a hassle because they are often sold in different locations and sometimes only in large quantities. Storing them can be challenging. If needed, Hoyafixation Hoya-mix medium is available for purchase by the liter. An alternative is a completely soil-free Hoya-mix, if you use or are considering switching to soil-free alternatives.

WATERING

Learn to recognize the dryness of the substrate. Some hoya growers can feel by the weight of the pot, others the lighter color of the substrate. The surest way to check the dryness of the substrate is to insert your finger deep enough into the substrate being careful not to damage the sensitive roots! Damp substrate feels cool to the touch while a dry one feels room temperature. If you are hesitant to water or not: skip it! Hoya are easy to kill by overwatering. The use of transparent pots is an excellent way to stay up to date with the moisture in the growing medium. This works especially well with cuttings in small pots, since our clumsy fingers will not fit into the pot without damaging the young roots! Make sure the substrate is dry enough before the next watering. Root rot kills Hoya faster than drying out.

Thick-leafed hoya store water in their leaves, so they may go longer between waterings. Checking the stiffness of the leaves will also help assess the need for watering. Well-hydrated hoya will have turgid leaves. Monitor your plant’s habits and water before the leaves wrinkle so you avoid stressing the plant unnecessarily. Checking leaf stiffness does not work always, however, because in cases of root rot caused by overwatering, the leaves also become soft. So when in doubt, check the roots!

Thin-leafed Hoya species generally need water more often than thick-leafed ones. Still, allow the substrate to dry between waterings to a depth of an inch (~3cm).

POT

The best advice: use the smallest pot possible! The root systems of hoya are relatively small compared to the leaf mass and do not need a large pot (for example, the picture of hoya cv. Mathilde splash, which is a 9-month-old young plant grown from a cutting in the picture, whose pot is only 8 cm in diameter). In a suitably small pot, the medium dries faster and there is no risk of root rot. And if the damage has already happened, you will notice the problem in time to save the plant. The small pot is especially important for newly rooted cuttings. In a pot that is too big, the cuttings will put all their energy into growing roots and leaf growth is delayed. A suitable pot size for newly rooted cuttings is 5-6 cm. Switch to a larger pot when the watering interval is only a few days, but only 1-2 cm bigger.

Hoya cv. Mathilde splash

In my experience, clay pots don’t work well for Hoya. Personally, I only use transparent plastic pots. Bonus: you can also easily monitor your plants for root pests. I recommend using a protective cover pot in which to place a transparent pot. This prevents algae from growing on the inner surfaces of the transparent pot.

LIGHT

During the winter season, the amount of natural light in northern Europe is not enough for Hoya. I recommend the use of supplimental light, especially if you can’t place your Hoya on a bright windowsill. Hoya carnosa is one exception and it can do quite okay in a dark room. But if you want to grow more special species and can't provide them with a southern window, you’ll need to add artificial light. Stores offer LED strips specifically for plants and even more powerful are the general-purpose LED bulbs with the E27 base. Just check that the light output is over 2000lm and the color temperature is ≥ 4000K. These can be placed quite close to the plants, at a distance of about 30-40 cm. Personally, I really like old fluorescent lamps, but their availability is quite poor with the industry transition to LEDs. Fluorescent tubes are not very environmentally friendly… There are powerful LED panel plant lights on the market that are unfortunately quite expensive. On the other hand, by buying one decent large panel, you save on the hassle of arranging multiple smaller systems and it’s more aesthetically pleasing in the home.

Many Hoya blush beautifully under strong light (sun stress). It’s the plant’s way to protect itself from the sun and, while pretty to look at, is not always beneficial to the plant. Intense light damages chlorophyll, which is the main pigment in plant metabolism. As a result, the structure of the leaf begins to break down. To combat this, Hoya produce anthocyanin, a brightly colored compound. This is reflected in the leaves in their reddish tones. That is, anthocyanin acts as a sunscreen for the plant! Sun stress is harmless if the Hoya blushes lightly, but don’t intentionally burn it too much (not even for the Instagram likes!). Pictured is an example of my H. surigaensis.

HUMIDITY

Hoya seem to grow faster in humid conditions. If your room humidity is too low (less than 40%), use a humidifier. Smaller hoya can be grown in mini-greenhouses or in translucent plastic boxes. To the aesthetic eye, terrariums or glass cabinets might serve as well. Keep in mind, in humid conditions the watering interval may be longer.

TEMPERATURE

The following table shows the general temperature tolerances at which various Hoya species perform best, based on information found in the David Liddle Hoya Inventory. It gives a general idea about which species will survive, for example, in the colder window of a house.

Low Temperature Hoya (10 ° C - 25 ° C)

  • H. bella
  • H. calycina
  • H. carnosa
  • H. compacta ‘Krinkle 8’
  • H. compacta ‘Indian Rope’
  • H. engleriana
  • H. fungii
  • H. globulosa
  • H. cv. Iris Marie
  • H. kerrii
  • H. lacunosa
  • H. lanceolata
  • H. latifolia
  • H. linearis
  • H. longifolia
  • H. motoskei
  • H. obovata
  • H. pauciflora
  • H. polyneura
  • H. pubicalyx
  • H. serpens
  • H. shepherdii

Average Temperature Hoya (15 ° C - 35 ° C)

  • H. albiflora
  • H. aldrichii
  • H. anulata 
  • H. archboldiana
  • H. arnottiana
  • H. australis ssp. australis
  • H. australis ssp. tenuipes
  • H. benquetensis
  • H. bhutanica
  • H. bicknellii
  • H. bilobata
  • H. blashernaezii
  • H. bordenii
  • H. brevialata
  • H. burtoniae
  • H. cagayenensis
  • H. callistophylla
  • H. calycina
  • H. camphorifolia
  • H. caudata
  • H. cembra
  • H. chlorantha
  • H. chuniana
  • H. cinnamomifolia
  • H. citrina
  • H. cladestina
  • H. coriacea
  • H. curtisii
  • H. cystiantha
  • H. davidcummingii
  • H. deykeae
  • H. diptera  (also H. 261, 266)
  • H. diversifolia
  • H. dischorensis
  • H. dolicosparte
  • H. eitapensis
  • H. erythrina
  • H. erythrostemma
  • H. excavata
  • H. finlaysonii
  • H. fischeriana
  • H. flavescens
  • H. flavida
  • H. graveolens
  • H. greenii
  • H. halophilla
  • H. hellwigiana
  • H. heuschkeliana
  • H. imperialis var rauschii
  • H. inconspicua
  • H. incrassata
  • H. incurvula
  • H. ischnopus
  • H. juannguoiana
  • H. kanyakumariana
  • H. kentiana
  • H. lamingtoniae
  • H. leucorhoda
  • H. limoniaca
  • H. litoralis
  • H. lobbi
  • H. loherii
  • H. macgillivrayi
  • H. macrophylla
  • H. magnifica
  • H. meliflua
  • H. meliflua ssp. fraterna
  • H. merrillii
  • H. micrantha
  • H. monetteae
  • H. multiflora
  • H. nabawanensis
  • H. naumanii
  • H. obscura
  • H. odettaea
  • H. odorata
  • H. oreogena
  • H. pachyclada
  • H. padangensis
  • H. parasitica
  • H. parviflora
  • H. paziae
  • H. pentaphlebia
  • H. picta
  • H. polystachya
  • H. pottsii
  • H. purpureo-fusca
  • H. pusilla
  • H. retusa
  • H. revoluta
  • H. rigida
  • H. rubida
  • H. samoensis
  • H. schneei
  • H. sipitangensis
  • H. subglabra
  • H. thomsonii
  • H. tsangii
  • H. vitellina
  • H. vitellinoides
  • H. vitiensis
  • H. wibergiae
  • H. sp. aff. micrantha

High Temperature Hoya (21 ° C – 35+ ° C)

  • all Eriostemma
  • H. anulata 
  • H. australis ssp. oramicola
  • H. australis ssp. sanae
  • H. clemensiorum
  • H. collina
  • H. cominsii
  • H. cummingiana
  • H. dennisii
  • H. densifolia
  • H. hypolasia
  • H. lambii
  • H. latifolia
  • H. marginata
  • H. megalaster
  • H. mindorensis ssp. superba
  • H. mitrata
  • H. montana
  • H. pachyclada
  • H. patella
  • H. ruscifolia
  • H. siariae
  • H. subcalva
  • H. walliniana
  • H. waymaniae

PROPAGATING HOYA

Based on my findings, here are some tips for taking cuttings:

  • bigger is NOT always better! On a cutting with many large leaves, the evaporation surface of the leaves is proportionally large, so a large cutting may not be able to take root because their energy goes to maintaining the leaves. For large-leaved species, a single-node cutting (1–2 leaves) are sufficient, for smaller-leaved species it is good to have at least 2–3 nodes.
  • the cuttings should be taken with clean sharp scissors. Sap fluid flowing from the incision site can be rinsed off under a warm water or wiped with kitchen paper. Hoya bonus: the sap is not irritating or dangerous to the skin. Awesome!
  • allow the cut to dry and callous for a day to prevent the stem from rotting.
  • take cuttings from hydrated mother plants. The best time to cut would be the day after watering the plant.

ROOTING CUTTINGS

Yleisimpiä juurrutusmenetelmiä ovat:

  • traditional water glass
  • perlite
  • peat (eg peat pellets or Growth moss)
  • moss
  • LECA
  • Lechuza Pon (pumice and lava rocks, zeolite)
  • Seramis
  • your own growing mix

As we can see, there are many options. I've tried them all. Some are faster and some slower. Although you can succeed in rooting hoya in a glass of water, I do not particularly recommend it because of the risk of stem rot. This method is perhaps best suited for leafy species. I also don’t like the use of moss in rooting hoya. Cleaning it later from delicate roots is tedious and the roots can suffer. If moss has been used to root the cuttings, a gentle cleaning must be carried out before transferring to the actual medium, because after wetting the moss stays wet for too long, but after drying it is difficult to get it moist again. My favorite method at the moment is ready-made peat briquettes, to which I add perlite. The last four rooting methods are very common among enthusiasts. The advantage is that the cuttings remain growing in the same growth base. This way the roots do not suffer from transplants and the plant starts to grow as quickly as possible.

If you bought an unrooted cutting, you should use the rooting method you are already familiar with. I recommend trying other rooting methods for your own cuttings, so a possible failure will not be so devastating.

Whatever rooting material you choose, the most important things in the process are these three things: heat, humidity and light.. Personally, I use either the mini-greenhouse in the picture (it also works great as a quarantine area for newcomers) or a translucent plastic box with a few holes drilled in the cover (alternatively ventilation every few days). For light, I use either an LED strip inside the cover or a more powerful light outside. A perforated plastic bag also works. A heating mat is also useful for cuttings, as heat accelerates plant rooting and root growth. The propagation area can be arranged, for example, on top of a household appliance (refrigerator, dishwasher, etc.) for warmth.

Keep the rootstock evenly moist. Here, too, I prefer transparent pots. The size can be 5-6 cm, for example recycled pudding jars are convenient. In a transparent pot, you can monitor the growth of the roots and the moisture of the growing medium (the moist substrate is darker in color). Rooting takes an average of 2-3 weeks, sometimes longer. Once the cuttings have taken root, their leaf structure will stiffen and you may already notice small signs of growth. At this point, the medium should be allowed to dry between waterings. However, do not let it dry to the point that new growth dries out. You can continue to grow the cuttings in a mini-greenhouse / plastic box / bag. I let my own sprouts stay in humid conditions under the lamp for at least the first half year. After that, I gradually start to get them used to the room air and natural light. Some of the more demanding species live permanently in a humid glass cabinet. In the winter, you should use artificial lights to keep your Hoya growing. Even the smallest lamp helps the plants to survive the dark winter in the north.

PLANTING A ROOTED CUTTING

When you buy rooted cuttings from us, do not rush to transfer it to your own growing medium, no matter the temptation. Shipping is a stressful ordeal for the plant, so let it recover in peace first. It is also not advisable to place the plant immediately under a strong lamp. In transit, it was in a dark package, so get it used to the light little by little for a few days. Since hoya thrive in humid conditions, it is a good idea to provide a place for them (eg mini-greenhouse, sealed plastic box, bagging. See Tips for Rooting Cuttings). Once the plant has settled in and gotten used to the new conditions, you can transfer it to your own growing medium. First, make sure the current substrate is lightly moist, so not too dry, or too wet. Carefully lift the plug from the current pot and gently shake off most of the peat. Not everything needs to be removed. We don’t want to damage those delicate roots! Choose the smallest possible pot (5-6 cm in diameter is suitable) which reduces the risk of over-watering. The cuttings also start to grow much faster when they don’t have to grow the too-big pot full of roots. After replanting, gently water the plant and move it back to the same moist place under the bulb. Keep the medium evenly moist but not wet until the cuttings have settled in place, ie have grown new roots in the new medium. Transfer the plug to a new pot (only 1-2 cm larger) when the watering interval starts to be 3-4 days.

Happy Hoya growing! 💚