Today is the day of the northern Winter Solstice 21st December.

For some it is a time for giving and many for taking – holidays, gifts etc. In Chiang Mai it is also a time for easy learning as some our worst forest weeds, or environmental weeds are in flower or are close to finishing flowering.

These photos were taken today at the Huai Keow waterfall and may we suggest all who go to the forest at this time keep an eye out for them as when they are in flower they are of course more conspicuous than at other times. So have a look, feel , smell and a gentle but firm pull to root out some plants and give the native plants an advantage.

Chromolaena odorata สาบเสือ

They are easy to hand pull as none has deep roots . Our first picture is of  Chromolaena odorata สาบเสือ which has powder blue flowers. This weed is regarded as one of the worst weeds of agriculture and bushland, and although it is extremely common at lower altitudes, hand weeding can markedly reduce its impact.

Lantana camara ผกากรอง, with red and orange flowers, has small thorns which are not at all like the nasty prickles of the three Mimosa weeds.

Lantana camara ผกากรอง


Lantana grows up to three straggly metres and to pull the roots out using gloves or an old cloth makes the job easier.

Mikania micrantha is a recently introduced weed to the north of Thailand and so far I have yet to see it in Nan but it does grow in Muang Phrae.  It is a monster plant climbing all over trees and depriving them of light as can easily be seen around Wat Umong.

Mikania micrantha has white flowers but by now most have set seed. As of writing no Thai name has been agreed on to my knowledge. The most common of the vernacular English names is “Mile-a-minute” being a very fast grower. Another is American rope because as it gets older the main stem appears like a knotted rope so perhaps we might call it เชือกอเมริกัน ?

Mikania micrantha

Mikania Leaf

This final and best photo of Mikania micrantha was kindly sent from the Christmas Islands, which means it really is a Christmas weed,  by Clive Heywood Barker.


Happy Weeding for 2013 a.d.


A fourth weed we add to this list today after this information from Eric Danell, of DokMai Garden, Hangdong :

“That would be Kalanchoe pinnata (Crassulaceae) ” ลุมลัง “or a similar species, probably one of the gazillion man-made cultivars. It is native to Madagascar and is invasive in e.g. Florida, but I guess only in sun-exposed areas. Each leaf can make many new plantlets.”

Well Eric guesses correctly about the sun-exposed area, as that is where it is most conspicuous at Huai Keow, where the flowers are a paler colour.

Weed  Madagascar