It’s actually a rather common frustration that many homeowners have: “What have I ever done to my hollies to make them refuse to produce berries? I’ve loved them and fertilized them and treated them with tender loving care, but still – no berries. My neighbor is awful and neglectful to his plants, and every winter his hollies are completely covered in fruit. Where did I go wrong?!”

Female yaupon

While these are both yaupon hollies, they’re different sex. This tree is female…

Photo Credit: Joy Goforth

Male yaupon

and this one is male.

Photo Credit: Joy Goforth

Savannah holly

Only female flowers contain fruit-producing ovaries, so only female plants – like this Savannah holly – can provide the berries that many gardeners admire.

Photo Credit: Joy Goforth

The answer to this berry dilemma lies in understanding the sex life of plants.

The majority of flowering plants produce “perfect” flowers, meaning that each flower contains male (stamen, anther and pollen) and female parts (stigma, style, ovary and ovules), as well as other important flower elements. But there’s also a group of plants that produce “dioecious” flowers: “Di” meaning “two,” and “oecious” meaning “house.” To better understand this concept, consider each individual holly plant as a “house.” The “boy” flowers live in one house, and the “girl” flowers live in another. Just like with humans, only flowers that contain ovaries can produce fruit, so it stands to reason that only the hollies with female flowers can make berries.

Unfortunately, there are no steadfast rules to identifying dioecious plants. Even when the plants are in full bloom, it’s often difficult to tell male flowers from female ones. If you’re purchasing a plant specifically for its ornamental fruit, you should do your homework first, or simply purchase the plants at the time of year they should be bearing fruit. (Just keep in mind that some plants won’t produce fruit until they’re more mature, making your hunt a little more challenging.)

Other than hollies (Ilex), the most common dioecious plant in the US is the juniper (Juniperus). Junipers aren’t necessarily grown for their fruit, but they do add interest to the winter landscape, and if they’re planted in an area with high visibility, the difference between fruiting and nonfruiting plants will be obvious. The acuba (Aucuba japonica) is also dioecious, and although its red berries aren’t a showstopper in the landscape, its foliage and fruit are excellent for winter cutflower arrangements.

As nice as berries are, fruited plants aren’t always the way to go. The ginko tree (Ginko biloba), for example, is a dioecious plant, but the female trees are best avoided because their fruit has a horrible smell. (Unfortunately, ginkos don’t produce fruit until they’re extremely mature, so your tree may be as much as 20 years old before you find out you’ve purchased the wrong sex.) There are other trees with messy fruit that are dioecious, too, like the Osage orange (Maclura pomifera) and Kentucky coffee tree (Gymnocladus dioicus). Depending on where you plant these trees, a male may be your best bet to keep litter cleanup to a minimum.

And there’s more to consider: If you want persimmons (Diospyros virginiana), you should purchase a female, but if you want showy flowers on your fringe tree (Chionanthus virginicus), you should get a male. For Japanese skimmias (Skimmia japonica), the males produce more attractive flowers, but the females have wonderful fruit. The list of dioecious plants also includes ash (Fraxinus), spicebush (Lindera), pussywillow (Salix), Sassafras, sumac (Rhus), Chinese pistache (Pistacia chinensis) and many more.

It may seem complicated, but it doesn’t have to be. Doing a little research on the sex life of a plant you want before you purchase it is just smart practice. Then you won’t have to wonder, “What am I doing wrong” when it comes to having fruit and flowers in your garden. And more importantly, you can enjoy the plants in your landscape the way you had hoped to in the first place.