Annual Vinca Sprouting Mysterious Offshoots

(Question)

I have always loved the colour that annual vinca brings to my garden. This year, I have observed something unusual occurring on the plants. There are yellow off shoots growing from them that look as if they belong to something else, but I can assure you they are indeed growing from the plant itself. I have never seen this before and I wondered if you might know what this is?

I had to shrink the photo down to meet your size requirements so please let me know if you have trouble seeing it. Thank you in advance!

(Answer)

Hello and many thanks for your question.  What you have there is Dodder Cuscuta.  It is quite unusual to see examples of Dodder in this part of the world. Dodder is a quite common but damaging plant in the tropics and more temperate climates.  It is known by many names such as Devil’s beard, Witches hair etc. perhaps because of its destructive nature. It is a parasite and a distant relative of the Morning Glory climber. Dodder can weaken or kill plants and reduce crop yields, it also makes infected plants more susceptible to pests and disease.  It a truly nasty specimen as it uses its specialized root system to search out its preferred host plant, then it coils around and inserts its roots into the plant, and feeds directly from the plant’s vascular system. Interestingly one of the plants it prefers as a host is periwinkle along with dahlias chrysanthemums and petunias.  It also attacks many crops such as asparagus, potatoes, and onions.  The good news is that it cannot withstand frost, so winter will kill it. But in the meantime, you should remove it immediately before it can flower and produce seed, as the seed will live in the soil and germinate next year.  Below is a link for more information on this parasitic plant. Please remember to destroy all pieces of this plant and put in the garbage – not the compost bin.  I wish you good luck!

https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/weeds/dodder.aspx#:~:text=Dodder%20is%20an%20annual%20seed,throughout%20the%20US%20and%20Canada.