Haworthia is a genus of dwarf succulents native to southern Africa. These succulents are well known for their ability to easily hybridize between species. This allows dedicated collectors and breeders to produce a wide variety of attractive and sought after cultivars. While these plants are relatively easy to care for, they can be tricky to pollinate. In this article, which is part 1 of our ‘Breeding Haworthia‘ series, we will discuss the best ways to conduct hand pollination of Haworthia and ensure successful, high-yield seed production.
The internal structure of Haworthia flowers
The first step in breeding Haworthia is to choose two different plants to cross pollinate. Haworthia are not self-fertile, so you cannot pollinate two flowers on the same plant. You can also not pollinate two of the same ‘clone’ produced in tissue culture, or otherwise propagated from the same mother plant.
Once you have chosen your plants, you will have to identify the male and female parts of the flower. This will help you better understand the whole process of pollination. Carefully remove the flower petals on one flower so that you can see the internal structures of it.
The male portion of the flower bears pollen and is called the stamen. This yellow pollen sits at the tip of each individual anther on top of the stamen.
The female portion of the flower is called the pistil. The stigma is the part of the pistil that you will be pollinating. It is a white structure that, in most cases, sits a little bit lower than the pollen. The pistil is attached to the ovary, which will turn into a seed pod once it is pollinated.
Do not let these technical terms confuse you. All you need to do is know that there is pollen which needs to be moved onto the white structure inside the flower. Now that you know what is happening on the inside of the flower, we can move on to the actual hand pollination of your Haworthia.
How to pollinate Haworthia flowers
The best time to hand pollinate Haworthia is early in the morning when it is still cool. We have found that earlier is better, as cooler temperatures seem to increase the odds of successful pollination. Evening pollination is also fine, but tends to yield less seed.
To pollinate, we use extra fine paintbrush hairs taped to a toothpick. Carefully insert the hairs into the flower of your first chosen plant. Gently move it around until it has picked up some pollen. Now, move it to the flower of the second plant and do the same. To ensure successful pollination, continue doing this back-and-forth at least 3 times per flower. Make sure to be extra gentle during this part of the process, as moving the paintbrush hairs too hard will cause the fragile stigma to break.
Some experts suggest removing the flower petals to provide better access to the internal flower parts. We find that the ‘natural’ way has a higher success rate for us. The ovary seems to be protected from the sun by the petals in the early stages of development. You may have more success in pollinating your Haworthia if you leave the flower petals in tact.
After this, the flower will begin to wilt, and should after approximately 1 week turn into a green seed pod.
After a further 3 weeks, the dark green lines on the side of the seed pod will begin to lighten in colour. This is indicative that the pod is about to burst open. This will scatter the seed everywhere, and make it impossible to harvest, unless cover the pods. We use large organza bags to cover the entire flower stem and all the seed pods once we have finished pollinating.
An added bonus to using organza bags is that it will prevent insect pests from eating, stinging or otherwise damaging seed pods.
Seed storage
As Haworthia flower throughout the year depending on the species, you may obtain some seeds during a time of year that is not ideal for sowing. You will have to store your Haworthia seed properly in order for them to remain viable.
The seeds are tiny and delicate, and if not stored correctly, they may not remain viable and may not successfully germinate. To ensure that your seeds remain in good condition, store them in an airtight container in a cool, dry place. A plastic pill vial is an ideal container. You can store this in a refrigerator, as it provides a consistent temperature and humidity level, which is essential for seed longevity. We have found that glass jars tend to induce mold growth and we do not advise using them to store your seed.
Congratulations, you have now completed the first step in breeding Haworthia! The next step will be to grow a plant from the seed that you have harvested. In our next blog, which you can read here, we will provide an in depth overview of sowing and germinating Haworthia seed.
Written by Harry Lewis, succulent specialist & conservationist