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Euphorbia Flanaganii Medusa’s Head Turning Yellow & How To Fix It

Updated: Feb 1

The weird and wonderful world of succulents never ceases to amaze. Would you think it possible a plant that looks like it has serpents growing out of it exists? Well, if you’re like us and love the strange succulents you’re in luck because such a plant does indeed cohabit with us on this earth.

Euphorbia Flanaganii aka the Medusa’s Head is an evergreen succulent plant that has gained popularity due to its symmetrical main head and thin long branches or ‘snakes’ growing from the sides, right around the head, resembling the mythical Medusa. Kind of.

Euphorbia Flanaganii medusas head
Euphorbia Flanaganii

Succulent enthusiasts from around the world have this plant growing in their collection and it seems many encounter the Medusa’s Head yellowing. So is this a problem? Is Euphorbia Falanaganii turning yellow slowly dying or is it just a mild reaction to changing environment and conditions?

Euphorbia Flanaganii can turn yellow for a variety of reasons. Too much water, too little water, winter, exposure to full sun/extreme heat and heavy succulent potting mix can all cause yellowing of the leaves or even the whole branches.

Although it may sound as if the Medusa’s head is a particularly picky plant, this isn’t necessarily the case. With the right spot and potting mix, this plant is likely to thrive even in the hands of a novice.

Let’s have a closer look at the Medusa and how to grow it successfully.


Euphrobia Flanaganii’s structure is very intriguing due to the swollen, above ground head. At closer inspection the lines visible on the head are very symmetrical and form small peaks. The top of the head is always visible, but as we proceed to the sides, long branches with tiny green leaves grow all around the head.

It seems that Euphorbia Flanaganii has developed a few forms, possibly due to cross breeding or mutations. Some Medusa’s Heads are darker in colour than others, some have thicker branches with leaves only at the ends and some have developed thin branches with leaves growing all over. Euphorbia Flanaganii is also prone to creating crests and even monstrose forms.

Euphorbia Flanaganii Medusas Head growing a crested part
This is quite an exciting photo as it shows exactly how Euphorbia Flanaganii can mutate into crested forms

In winter, Euphorba Flanaganii seems to be dormant and can loose all its leaves. This is one of the reasons for the plant yellowing and is quite natural. Not much can be done about natural yellowing other than keeping your medusa's head in a heated greenhouse with artificial light when the days are short. The yellowing should not be extensive and normally only applies to leaves and, perhaps, a few bottom branches.

The plant spreads by creating new heads on mature branches which will, in time, develop their own set of branches (photo below). The branch usually becomes swollen at the end.

Euphorbia Flanaganii also produces yellow flowers a couple of times per year. The flowers are small and once the plant is mature, can cover the head as well as the branches. If pollinated, a seed pod is produced and the plant can be successfully propagated this way.

Euphorbia Flanaganii flower
Euphorbia Flanaganii flower

As with all Euphorbias, Flanaganii is filled with white sap which will come oozing out when the plant is injured. This sap is toxic and should not get on the face or in the eyes.

Position & Care

Euphorbia Flanaganii can be found in nature, in arid regions of Africa, Madagascar and Canary Islands. The temperatures are naturally quite warm throughout the year.

Having grown many thousands of these plants in our nursery, we found the biggest influence on the plants appearance and its yellowing is winter and exposure to direct sun during heatwaves over 35C (95F).

Medusa’s Heat can withstand the heat of over 45C without any adverse effect to its look, but it has to be shielded from direct sun’s rays. We found that the best spot for it throughout the year is under a 30% shade-cloth. If your plant is yellowing in summer and is exposed to sun, move it in bright shade and keep watering. Euphorbia Flanaganii is not frost tolerant and will need to be protected from freezing temperatures.

While this plant likes a bright shade, it needs lots of indirect light to grow compact and pretty. We have heard from some of our customers that Medusa can yellow if kept in too much shade indoors.

Although Euphorbia Flanaganii can be kept indoors, it should be in an airy spot by a bright window. Some sun coming through the window will not hurt the plant. Having said that, in summer when it's really hot, the afternoon sun can burn any plant left immediately behind glass.

In our experience, water and humidity do not pose any problems for these succulents and, in fact, in summer, they like their potting mix to be kept just a little wet all the time. We have also seen yellowing in summer during droughts, but as soon as the plant was watered well, the green growth came through once again. We water this plant quite often (every other day in summer), but never let it sit in stagnant water.

Euphorbia Flanaganii prefers a good quality potting mix, if planted in pots. In the garden it does not seem to mind being planted in ordinary soil. This plant should not be planted in pots using just soil, only succulent potting mix.

Sometimes young plants can grow too many branches, but not enough head. We cut these long branches off while the plants are still quite small to encourage the swelling of the head. This will not hurt the plant and it will also grow out of the ‘damage’ done by cutting the branches.

Please wear gloves when cutting or handling this plant so the sap does not accidentally get on your face or in the eyes.


The best and quickest way to propagate Euphorbia Flanaganii is to let your plants mature and wait for the branches to turn into a head which will start growing its own branches. This growth can be cut off, left to dry for a day and planted in succulent potting mix.

Only propagate in the warmer months (mid spring- summer). During this growing period, the cuttings should root in about 3-4 weeks. We water our cuttings every few days.

To not get a tall Medusa, plant your cutting in right to the head level.

Seed propagation is possible but very slow. If you want to go down this road, make sure the seeds are from a reputable seller.


Euphorbia Flanaganii only gets bothered by mealy bugs and they often go straight to the roots. On the odd occasion, they can be found in the branches too.

It may be a good idea to re-pot the Medusa’s Head at least once per year to check on the roots and provide new nutrients in the form of fresh potting mix.


The Medusa’s Head can be very toxic to some people and pets. We have so far not experienced any adverse effects and our dogs frequent the greenhouses as well, but if you have young children or pets that chew on plants it may be a good idea to keep this plant out of reach or give it a miss altogether.

Where Can I Get It

If you’re in Australia our nursery sells rooted Medusa Cuttings or Mini Medusa's. Elsewhere in the world you may find Euphorbia Flanaganii in garden centres or online. It is not a super rare plant, but can be a bit hard to source.

Our nursery Fern Farm Plants sells Euphorbia Flanaganii in Australia

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