Why Do Cats Go Nuts Over Weigelas?

Question: My 7-year-old cat has discovered my weigela bush. During flowering, he climbs into the shrub to grab the flowers, rolls around in it and meows happily. Honestly, he seems to be high! I have many other plants, but he leaves them alone. It’s really very funny. Do you know why this happens?

H. Filteau

Answer: You’ve hit upon a situation that is fairly well known to cat-lovers, but one that has not yet, to my knowledge, been studied. Some cats (a small minority) do indeed seem to adore weigelas, but others are completely indifferent to these shrubs.

I think it’s safe to presume that weigelas (or at least some weigelas) give off a chemical compound of the same type as nepetalactone, the terpene that makes catnip (Nepeta cataria) so attractive to many kitties. Other nepetas (Nepeta spp.) also give off this product, but to a lesser degree. In fact, protecting ornamental nepetas against overenthusiastic kitties was the subject of a recent blog: Protecting Nepetas From Cats.

A Repellent With a Feline Side Effect

If the catnip produces nepetalactone, it’s as a protection from predatory insects. Nepetalactone is a recognized insect repellent and few six-legged pests will attack catnip plants. Its side effect, that is, attracting cats, is less desirable … for the plant at least. But cat owners have a lot of fun watching their tabbies interact with dried catnip leaves, often added to cat toys.

Similarly, some cats avidly rub up against and roll around in honeysuckles (Lonicera spp), including Tatarian honeysuckle (L. tataricum), and it also produces nepetalactone. In fact, honeysuckle shavings too are sometimes added to cat toys.

Kiwis (Actinidia spp.) produce a different product that attracts and intoxicates cats in the same way: actinidine. The silver vine kiwi or matatabi (A. polygama) is particularly rich in actinidine. In fact, in the Orient, silver vine sticks are more often used in cat toys than catnip.  

In my own garden, a brown and white cat often rubs against and scratches my female arctic kiwi (A. kolomikta), obviously in ecstasy. Oddly, she never touches the male vine. Maybe my female cultivar, ‘Ananasnaya’, is richer in actinidine than the male? Curiously, other cats in the neighborhood seem indifferent to both.

Valerian (Valeriana officinalis), an ornamental perennial, medicinal plant and, in many areas, noxious weed, also produces actinidine and will also attract cats.

Finally, cat thyme (Teucrium marum) produces another component that makes cats go a bit nuts: dolicholactone, chemically very close to nepetalactone. It’s occasionally grown as a cat plant.

How cats respond to these various products differs from one individual to another. Some only react to nepetalactone, others only to actinidine and others only to dolicholactone, others to two or all three and finally, some cats simply don’t gain any euphoric effect from plants of any kind. Also, the reaction can also vary depending on the conditions: for example, some female cats don’t react to these products during pregnancy, but resume once their kittens are born.

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Now what we need is a scientific study of exactly what compound in weigelas attract cats … and then I’ll have an appropriate answer to your question!