Ants in love with my Rheum

[Staale]

I am the lucky owner of a Rheum alexandre. However, this summer I have noticed that I am not the only one in the garden to appreciate this plant. Small black ants, of which there are many all over the garden, have fallen in love with the plant, and repeatedly insist on building their nest around its base. The plant itself looks happy, but I'm not sure if this is a healthy situation in the long run.  I have so far refrained from chemical solutions, but tried to brush them off on occations.


Should I go to war, or will the plant be OK with the ants living there? Could there be a symbiotic effect involved?

I should add that there are also aphids on the plant (wich I believe is a very common problem with Rheums), and the ants tend to these as they do on aphids on other plants. The plant also emit a clear gelly substance which I believe is a defence against aphids. A nearby Rheum delavayi seems altogether untroubled by ants.

 

[Maggi Young]

Staale, this is an interesting question. We do not have many ants in our garden so I cannot advise you. Good luck, though, with growing the Rheum alexandre to its full glory. We will, of course, be expecting a photo of the flower stem when the time comes!

[Susan Band]

I have had the same problem with my Cremanthodiums, in quite a few different species of them. I got rid of the aphids and the ants moved out too. I don't know how serious the problem is but they can move a lot of soil away from the roots which can lead to problems on dry weather. At the moment the ants are under my windowsill and dump all their waste into my livingroom. Watch out for your trillium seed, they love that.

[Staale]

Oh yes
I always keep an eye on the Trillium seed pods. I usually harvest before they are completely ripe, and when sowing the seed in the ground cover them with fleese til spring arrives. At that time it seems the ants no longer find them attractive.

I will consider targeting the aphids, then. I have been worried that the Rheum might not respond positively to the chemicals involved, but maybe it won't mind.

[Lesley Cox]

Once established, Rheums are pretty tough. I have  which has interesting knobbly foliage but I rarely get to see it as possums eat every leaf within days of it sprouting in spring. But it still survives and comes again next time.

[Paul T]

Here, ants commonly farm aphids and scale insects.  They "milk" them for honeydew as food.  If you get rid of the aphids the ants should disappear, plus if you get rid of the ants the aphids don't spread amongst your plants as easily because the ants aren't carrying them from plant to plant to increase their "farm" area.

Some sort of systemic pesticide would work well, otherwise a pyrethrum spray if there's only a small area and you're able to get to all surfaces.  I tend to use the systemic myself, and they're then pest-proof for the next couple of months.  Has done wonders for the Azaleas/Rhododendrons.... no more lace bug.  3 sprays a year and there's no more silver leaves.  Has been that way for about 4 or 5 years now since I started doing it rgularly during the growing season.  Not aphids of course, but you get my meaning I think.

Good luck!! 

P.S.  Lesley.... you have a smiley face with interesting knobbley foliage?  That must be uncomfortable for you!? 

[Staale]

Thank you all for kind advice. The plant looks sturdy enough, so I will dare mine to be as resilient as yours, Lesley.
 Hope you and your Rheum beat the possums to it next season.

When on to the subject Rheums. I mentioned earlier that I have a R. delavayi. The plant is from seed (seed exchange), and is now some four years old, and still only som 10 cm (3 ") and has never flowered. Should I be pleased with it's size, or is it telling me that it disaproves of the conditions it grows in? I have never really found a good source on information about this genus, so am not really sure what to expect.

I will keep you posted on the results of the chemical cleansing.

[Lesley Cox]

While I love all the 8 Rheum species I've grown, I love R. delavayi most of all, simply BECAUSE it's so tiny compared with the others, Staale. Mine grows to about 12cms in bloom, just 3 or 4cms when only in leaf. It is quite deciduous and is creeping to make a good mat. The flowers are red, filled with cream pollen and I get some fertile seed each year. It should be sown fresh. I like the red veining in the foliage too. Mine is in a moist raised bed and seems very happy there. The current 3 plants were raised from seed from the ACE expedition (ex AGS or SRGC seedlist) but my original plant 26 years ago was given to me by the late Tony Colmer, when I stayed with his family in 1981. I am very fond of it for that reason too.

There's a picture somewhere on an old thread but I'll put it here too, being too lazy to go searching.





In the first pic, the Primula x juliana `Snow White' gives a good idea of comparative size. The Rheum is at home with little things like Houstonia caerulea, Hacquetia epipactis and very small primulas.

[Staale]

Thank you for the information, Lesley. Apart from the creeping part, wich it has shown no interest for, it is just bit shy, then. And I agree, it IS a lovely little plant in its own way, with beautiful red stained leaves. Another good thing that I didn't know; I guess that if it some times is inclined to creep, it is not going to die on me straight after flowering (if it ever comes to that).

[Lesley Cox]

It should be fully perennial, and quite hardy as well.

[Staale]

Just wanted to thank all who responded to my question about ants building nest around my R. alexandre. Problem is now solved, and remarkably easy it was too. A quick go with weapons of mass destruction (chemical spray), and they were all gone the next day, both aphids and ants. I'm very grateful, and I'm sure the Rheum is too!
Funny though, that the ants not only 'milk' the aphids for honey dew, but that they practically try to move in with them.