I have 2 croton plants – both are about 30+ years old. One is in a large bathroom with a skylight and is very healthy. I don’t think it has ever had seeds. The other is in a sunroom, facing west. It grows sticky seedy things quite often, which I always snap off. It is very sad and losing lots of leaves. The sick plant is about 3′ tall and about 3′ in diameter. The healthy one is about 3.5′ tall and about 3.5 feet in diameter. I water both of them thoroughly once a week. Can I save the sick plant?
Your record life span of two colourful houseplants indicate you have been caring for your Crotons very well. The current issue with one of these Cadiaeum Variegatum plants may be related to a few problems.
Crotons will lose their leaves through drooping and dropping if the plant has been damaged in any way. Check the leaves that are drooping, following your fingers along the stem to see if there is breakage. The sticky sap is usually an indicator of injury, along with a callous forming on a stem somewhere.
These similar symptoms may also be a sign that the plant is becoming root-bound in the pot. Examine new growth around the base of the plant where it emerges from the potting medium. If this area is green and healthy, you may wish to repot with new growing medium in a slightly larger pot.
I see what looks like scale on the leaves, a very common houseplant disease, although, again, it seems unusual given the many years of good health. Remove these leaves, and hope your plant will recover its vigour and colour as the light increases during the season.
For more complete information, refer to the University of Florida information sheet.