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Darwin Correspondence Project

From J. J. Weir   28 April – 4 May 1868

6 Haddo Villas | Blackheath SE

28th April 1868

My Dear Sir

You have paid so much attention to climbing plants that I feel it is presumptuous on my part to write on the subject.—

Root climbers were however by you treated at less length than the other classes of climbing plants, it is therefore just probable that I may be able to point out a few facts which have escaped your attention in the genus Hedera.—1

It is now ten years since I commenced to cultivate green & variegated Ivies & I have now about two dozen distinct varieties.—

It is said that our cultivated varieties are descended from but three species viz Helix, Canariensis, & Colchica but I am of opinion that there are more true species in our gardens.—2

I was struck by the fact that of most of the principal varieties these are purely arboreal forms.—

I have those of Helix both plain & variegated and with yellow berries.—

Now my point was how are these arborescent forms produced.—

My experiments are but three years old but they have been successful.—

I took off from one of the varieties shoots which would if left on have probably produced fruit, these I placed in pots in a cool frame about the month of July 1865, the slips remained alive but without producing a leaf until the Spring of 1867, they then began to grow, & this Spring have made still more considerable progress both in the main & side shoots, but the plants are perfectly arborescent, the stem is quite round entirely without rootlets, the leaves are arranged around the stem without having any exactly above each other, as many as six leaves being developed before one is produced approximately perpendicular to the first.—

This is a very great alteration of the phyllotaxis   the ordinary clinging shoots have the leaves alternate on opposite sides & the stem being more or less flattened to the wall or object to which they adhere.—

Shoots taken from these would grow in three years to a height of 3 or 4 feet but the shoots from the arboreal part of the Ivy with simple ovato-lanceolate leaves would not be more than 12 or 14 inches in height at the same age.—

After writing thus far I had an opportunity of mentioning my experiment to Dr. Hooker,3 he said he was unaware of the fact but the result was what he would have expected.

Continued May 4th.

With regard to the variegated varieties, some come quite true with each leaf edged with either gold or silver (in gardeners language) others are more or less blotched with a tendency to produce branches all cream colored or all green; some become all over of a very pale sulphureous green & are then very slow of groth, & others, I think the most remarkable, produced beautiful golden shoots in spring nearly as bright as a buttercup, followed at Midsummer by shoots bearing leaves entirely green, but I have seen none like some of the varieties of Hollies or Eunanus with the lighter colors in the centre of the leaf and edged with green.—4

In those cases where Hedera Canariensis or H Algeriensis sports to cream colored leaves only, the branches become very tender & ultimately die, but I have had H Helix for eleven years without producing a single green leaf or a green spot & still living but very stunted in growth, the plant not being now more than two feet in height but with several branches of a very “twiggy” character.—

Yours very sincerely | J Jenner Weir

C Darwin Esqr.

CD annotations

10.1 This is … phyllotaxis] double scored pencil
13.1 Continued … character.— 15.5] crossed pencil
Top of letter: ‘I have often marvelled at change *of growth of flowers & creepers [interl] in Ivy—but I had no idea that the change [was] so permanent as you show— I am particularly surprised to hear of change of roots. There is a tropical root climber (I forget name) which changes almost in same way as ivy | How many subjects you have attended to’5 pencil


For CD’s treatment of root-climbing plants, including a reference to Hedera helix (English ivy), see Climbing plants, pp. 105–7. The section on root-climbers remained unchanged in the second edition, except for an additional note on the aerial roots of a Brazilian plant (Climbing plants 2d ed., pp. 185–8).
Weir refers to Hedera helix, H. canariensis (Canary ivy), and H. colchica (Persian ivy).
Joseph Dalton Hooker.
The genus name Eunanus is a synonym of Mimulus (monkeyflower).
CD’s annotations are notes for his reply; see letter to J. J. Weir, 7 May [1868].


Climbing plants 2d ed.: The movements and habits of climbing plants. 2d edition. By Charles Darwin. London: John Murray. 1875.

Climbing plants: On the movements and habits of climbing plants. By Charles Darwin. London: Longman, Green, Longman, Roberts & Green; Williams & Norgate. 1865.


Observations on root-climbers. Variegated and arborescent varieties of Hedera.

[CD’s notes are for his reply, 6165.]

Letter details

Letter no.
John Jenner Weir
Charles Robert Darwin
Sent from
Source of text
DAR 181: 77
Physical description
12pp †

Please cite as

Darwin Correspondence Project, “Letter no. 6145,” accessed on 21 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 16