Holly and hydrangeas

(Question)

We have clay soil and live near Edwards gardens. In front of our house we have hydrangeas and a pair of hollies male and female.
We had to replace the male holly last spring and it is much smaller than the female holly. One hydrangea is very close to the male and becomes much bigger and overshadows the male holly. This hydrangea has large conical blooms. Should I move that hydrangea and as well get a newer small female hydrangea.
Also I have a pink blooming hydrangea which hasn’t bloomed in the last 2 years. We live near Edwards Gardens in Toronto. Our hydrangeas get partial sun and lots of water. We didn’t get any holly berries this last year.
Thank you

(Answer)

How fortunate you are to live near Edwards gardens and the Toronto Botanical Garden–no doubt you are able to visit the gardens regularly and take inspiration from them.

You mention that you have concerns about the hydrangeas and hollies that are growing in the front of your house. Which direction does your front yard face? North, northeast, east? Do you have large trees that shade the sun? Terms to describe the amount of sunlight are not easily defined; “partial sun” can indicate anything between 3-6 hours of direct sun per day–“full sun” usually means 6 or more hours of direct sun; “partial shade” between 2 and 4 hours. The amount of sun that your plants get will affect how the plants grow, bloom and/or create berries.

You have more than one hydrangea; you are possibly aware that there are a number of different species and some species have even more cultivars. Nevertheless, most can be identified by their leaves and flowers. The hydrangea that “overshadows the male holly” and “has large conical blooms” is most likely Hydrangea paniculata; this species has many different varieties and cultivars such as the popular ‘Limelight’ or ‘Grandiflora’ (commonly referred to as PeeGee–H. paniculata ‘Grandiflora’). Oak-leaf hydrangea (Hydrangea quercifolia) is a native species that also has conical-shaped flowers; the leaves resemble those of the red oak tree.  Both the H. paniculata and H.quercifolia can become sizable shrubs.

The “pink blooming hydrangea which hasn’t bloomed in the last 2 years” is probably a cultivar of Hydrangea macrophylla, which translates to “big-leaf” hydrangea. Its mophead-shaped or lacecap-type flowers bloom in shades of pink to blue depending upon the pH of the soil–pink in alkaline soils, blue in acidic soils.  Generally, H. macrophylla are borderline hardy in Toronto. It is recommended that they be mulched year-round with 2-3 inches of shredded bark or compost and be sited in a protected area of your garden. However, most will simply not bloom when winter conditions such as we have experienced in the past couple years (e.g. low temperatures, wide temperature fluctuation, icy conditions, late frosts) are present. There is a cultivar, Endless Summer, which produces blooms on new wood as well as the old wood; it is hardier than the species. For more information, you can check out the link below. Even if you have this cultivar, it still may have been affected by the unpredictable weather and occasional drought conditions that Toronto has experience during the recent spring/summer/fall seasons. As you are aware, most hydrangeas need moist, well-drained soil in sunny or partial shade areas; even though your clay soil may hold moisture, it may not be well-drained or be able to easily absorb accessible water. Another thing to consider is the importance of sheltering hydrangeas from the prevailing and drying NW winds, especially if the plants are located on the north side of your house.

With respect to your hollies (possibly Ilex x meserveae Blue Prince and Blue Princess), you indicate that the hydrangea is very close to the male holly that you replaced last spring; you would like to know if you should move the hydrangea or add “a newer small female” holly (?). Actually, it might make more sense to move the smaller male holly than the hydrangea. However, the hydrangea can be easily pruned and maintained at a smaller size. Where is the female holly in relation to the male? They don’t really have to be next to each other to ensure pollination and good fruit set; several meters between them is fine. Having another female might be an option as one male plant is sufficient to pollinate several females.

Hollies do prefer moist, acidic and well-drained organic soils; clay soils are alkaline.  If you’ve had berries in previous years, then the lack of holly berries this last year may be due to the extremely cold winter conditions we experienced in 2014/15 and not necessarily the pH of your soil. Even though the pH of one’s soil (lowering the pH from alkaline to acidic) can’t be easily changed, adding several inches of organic matter (compost, composted pine bark) to your soil each year will gradually produce a better draining soil structure for the hollies.

It’s difficult to really assess what you have without having more information about the site where your shrubs are growing. The weather conditions of the past few years have most likely contributed to the lack of blooms and berries on your shrubs. Even so, given the information that you have provided, more sun would enable both the hydrangeas and hollies to produce more flowers and berries.

Thanks for contacting the Toronto Master Gardeners. We hope that your shrubs will once again bear plentiful flowers and bright red berries.

Here are some links you might find helpful:

Endless Summer Hydrangea macrophylla —https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=b383

Hydrangea quercifolia–https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=d380

Ilex x meserveae Blue Princess–https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=d470

Ilex x meserveae Blue Prince–https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=d460