Running Late With Magnolias

A few years ago I wrote a column about magnolias, and I admit that I have a special place in my horticultural heart for this tree and its fragrant but short-lived, sensual flowers. But as I noted then, the variability of spring weather means that about two out of every five years the flowers get toasted by frost before they adorn the trees. This year, however, when it was 12 degrees at the end of the first week of April and in the upper 70s just two weeks later … well, the magnolias were confused, as were many other growing things.Upstate, the magnolias were fine, and they are just at peak flowering. In Westchester many of the magnolias opened for a day, only to get totally frozen when the temperature bottomed on April 6 at around 10 degrees. Out here, the cooler temperatures stalled the magnolia flowers, and many were just opening around April 13 with little to no damage.

But I did notice one interesting thing in Westchester. While most of the magnolias there had their flowers open, then freeze, one particularly beautiful specimen that I marvel at each spring opened and flowered gloriously for nearly a week. So how did this magnolia flower in spite of the freeze, and what lesson may it be teaching about climate change?

The answer is simple and it’s opened up an entire new train of thought for me when it comes to climate change and how that is affecting our gardens and landscapes. This magnolia’s secret to flowering in spite of the freeze is that it seems to be a variety that flowers 10 days later than the more common magnolias. When it got bitterly cold, its flowers were still tightly furled and protected from the chill. So, what’s the lesson? It’s a bit more complex than it seems.

We know from historical data that our growing season is now longer at both ends than it was as little as 50 years ago. Spring, as measured in temperature, seems to arrive a week to 10 days earlier, and the end of the gardening season, based on our first hard freeze (as opposed to frost) seems to come a week later in the fall. Therefore, it’s not illogical to think that wow, we can garden longer. But the magnolias say maybe not. Yes, our average growing season is getting longer, but I don’t think that’s going to be happening reliably every single year. Like this year. All it takes is one Alberta clipper or polar vortex, which can be highly unpredictable, and—zap—there go your magnolia flowers, apple blossoms or early garden greens. Easy enough to protect the veggies from a sudden cold snap, but not so easy to cover your fruit trees or keep the frost off the fruit blossoms.

Here’s where the magnolia that was unscathed this year may teach a lesson. It was a late bloomer. Want magnolias that are much more reliable than those that get zapped every other spring? Plan late-blooming varieties. Want fruit trees that don’t have their blossoms blasted by that one night in early April when there’s a hard frost? Plant later-flowering varieties. It takes some homework, but even among apple trees of a specific variety, let’s say Fuji, you may be able to find a cultivar that blooms a week or two weeks later than those commonly available. Again, it will mean some research on your part and you won’t find these plants at the big box stores, but you will find them at specialty nurseries or by very carefully reading the catalog descriptions.

Find a nursery that grows only apple trees. Find a grower that grows only magnolias or has magnolias as one of its mainstays. Get the idea?

Another plant that I adore is the tall garden phlox or Phlox paniculata. I love their scent, the range of colors and the fact that they bloom so late in the summer garden—but most of all I use them for cuts and love to have them in the house.

They have their issues, though. Some varieties have a tendency to get a leaf spot that can be unsightly. It really doesn’t bother me, though, because I strip off most of the leaves since I’m using most of the ones I grow for cut flowers. But in the garden it can be an issue. They also seem to be a magnet for the two-spotted spider mite. The mites show up early in the season—like now—in small numbers, and then as the season progresses and we get some hot and dry weather they multiply like crazy. The result is foliage that yellows and curls, so again they can look awful in the garden. And the mites seem to stifle the plants, which look tired and beaten come August and September. And last, but not least, there’s the powdery mildew which also makes the foliage look awful. Take good care of your phlox now and they’ll do much better come flower time.

If you’re in the market for this garden perennial, they can be found in every garden center and from just about every mail order nursery. However—and yes you knew this was coming—there are phlox that are OK, and then there are phlox that are great. How do you know which are great? Well, you can start by pasting this link in your browser http://goo.gl/oxF81r. It will take you to a research project, one of 39 to date, by the Chicago Botanical Garden where they trialed Phlox p. over a series of years, testing for a number of characteristics including mildew resistance. It’s an incredible resource.

Here are some additional tips. If you have these plants in your garden you should be thinning out the crowns now by removing about half of the new shoots. The shoots will be 2 to 3 inches tall and are easily pinched out at ground level. This allows for air circulation as the shoots develop, and stronger stems develop on the remaining shoots.

Better air circulation can mean less mildew. Keep in mind, though, that mildew resistance is just that … resistance. It’s not a guarantee, and a resistant variety may be resistant one summer and not the next. You may even find that if you have two identical varieties in two different locations on the property, one may have mildew and one may not. Whatever you do, don’t water these plants from above, as keeping the foliage wet, especially overnight, encourages the spread of powdery mildew. Learn how to spray the mites away with water. Mites can be controlled with organic sprays such as very light summer oils and some fairly safe insecticides, but be careful, because some insecticides actually encourage the mites. Divide the plants every three years.

And about your lawn mower. I always do my first cut very high with last year’s blades. Let the old blades take the brunt of the twigs, nuts and debris on the lawn. Then put your new blades on. Before your first cut of the year, change the oil and change the spark plug as well. If you keep gasoline stored in a container and add a little to the mower every week by topping off the tank, add a fuel stabilizer to the fuel in the container every time you fill it. This way you never have to guess if the fuel in your tank is “stale” or not. Keep growing.