Acer palmatum ‘Twombly’s Red Sentinel’


Hello master gardeners.
I bought one Acer palm, twombly red sentinel last year. i was under impression that like other japanese maple my tree will grow red leaves all the time but no ! leaves of my tree tuened green during summer time. I felt so sad. I am not sure if it is natural or there is something to add to its soil to get red leaves in summer. I will be thankful to you if you give me some info on what can be done to have red leaves. Thank you.


Thank you for contacting Toronto Master Gardeners.  The descriptions I’ve read for the leaf colour of your Japanese Maple (Acer palmatum ‘Twombly’s Red Sentinel’), refer to leaves emerging as bright red in the spring, then deepen to burgundy, followed by red-green in the summer.  When fall arrives, the leaves change to a brilliant pink-red or orange-red colour.  This variety of Japanese Maple is frequently purchased to experience these colour changes throughout the 3 seasons.

Japanese Maples can be quite variable in their colour, even within the same variety.  It all depends on the tree. With that said, the leaf colour of some Japanese Maples may be influenced by sunlight. Leaves may turn greener in shade, while on another tree, intense summer sun may result in greener leaves.   It is quite common for “red” Japanese maples to become more green in the summer.    Due to this variability, if you’re looking to buy a Japanese Maple that remains purple or red throughout the seasons, your best time to shop for one is mid-summer.

As far as I’m aware, there is nothing you can add to the soil that will change the leaf colour of your Acer palmatum.   Relocating your tree to a sunnier location (if it’s not already in sun), may bring out brighter red/burgundy leaf colour.  But there’s no guarantee.  Note that some Japanese Maples prefer morning sun locations as afternoon sun can scorch their leaves.

This article from Monrovia explains the issue.

Enjoy the unique changing colours of your tree – from Spring to Fall.