These June-blooming flowers were started by winter sowing. Photo: C. Carignan
Winter sowing is a technique gardeners can use to start growing seeds outdoors during the winter months. If you have limited space for starting seeds indoors, winter sowing might be an option for you, depending on what you want to grow.
I first tried winter sowing last year with several types of flower seeds. Winter sowing works best for plants that are cold tolerant or even require a period of cold in order to germinate. When you are looking at seed descriptions, look for words like “cold tolerant,” “cool season”, “hardy annual,” “perennial”, “sow in autumn”, “sow in early spring”, or “self-sows”. These words indicate the best candidates for winter sowing. Continue reading →
Q: Why are my orchid leaves turning yellow and drying up? The plants are located in the bathtub where they get sun daily from the south and west window.
A: While it is normal for the oldest leaves of moth orchids (Phalaenopsis) to turn yellow and dry up as they age, when there is uniform yellowing and shriveling of newer leaves, it is a sign of distress. The shriveling suggests there is a lack of water reaching the leaves. Check the root system of your plant. If the roots are in poor condition, they cannot take up water. Overwatering can cause roots to rot. If you haven’t repotted your orchid in a couple years, the potting medium may have broken down and become too dense to allow for good drainage. Bacterial rot also can occur if water is allowed to sit around the center shoot or in the leaf sheaths for a long period of time. Water only in the morning so that your plants can dry out by nightfall. Never let them stand in water and keep the plants in a location where they can get good air circulation, indirect light, and a warm daytime temperature above 75F. Watering instructions can be found in our orchid care video.
Photo: Beth Bukoski, University of Maryland Extension
Q: I found these orange bugs all over the milkweed I planted for Monarch caterpillars. What are they and what, if anything, should I do about them? I don’t want to harm other organisms.
A: What you have here are nymphs (juvenile stages) of Large Milkweed Bugs (Oncopeltusfasciatus). At this time of year, it is common to see these insects on different species of milkweeds throughout Maryland. The gray and black “insects” in your photo are actually cast skins of the young nymphs. Large Milkweed Bugs go through five instars (phases as nymphs) and shed their exoskeleton at each phase until they become fully developed adults. Continue reading →
Cardinal Flower (Lobelia cardinalis). Photo: C. Carignan
I gave up on my hummingbird feeder years ago. It was more than I wanted to do to keep up with changing the sugar solution every two to three days, as recommended to keep the food free of spoilage that could be harmful to the birds. I saw that hummingbirds would visit some of my garden flowers just as much as the feeder, so I decided just to provide flowers for them. More flowers for me, more natural nectar for them. A win-win.
In my garden, ruby-throated hummingbirds most often fed at my scarlet bee balm, blue salvias, brilliantly colored zinnias, and orange butterfly weed. This year they have an additional choice that appears to be their new favorite. It is the flower whose color resembles that of a different bird, cardinal flower(Lobelia cardinalis).
This Maryland native plant produces 2-4′ tall spikes of bright, cardinal-red flowers that are irresistible to hummingbirds in mid to late summer. In fact, hummingbirds are an essential pollinator of these plants.
Cardinal flower was easy for me to grow from seeds sown directly outside. In the fall of 2016, I scattered seeds in a low area of my yard where water frequently would puddle after heavy rain. They sprouted and grew low foliage and a few small flower spikes the following season. This year I have plants that are well established and the flower spikes are tall and brilliant. Cardinal flower grows best in moist to wet soils, so this has been a fabulous year for it!
If you have a shady or partially shaded area that tends to stay moist in your yard, cardinal flower might be a great choice for you. Allow these plants to reseed naturally so you’ll have flowers — and a natural hummingbird feeding station — year after year.
Q: My hydrangea bloomed white but instead of turning red it turned brown. What is happening to the petals and what can be done?
A: A disease called Botrytis blight can cause spots and browning symptoms on the flower petals of Hydrangea and other types of flowers as well. Extended periods of cloudy, rainy weather like we had recently can favor the development of this fungal disease. Botrytis first appears as water-soaked spots that gradually expand into brown blotches. There is no remedy for this damage. Prune out and dispose of the damaged flower parts.
The spotting on the leaves is common on Hydrangeas in late summer, especially in our humid climate. Leaf spots can be caused by fungal and bacterial pathogens. The leaf spots are mainly a cosmetic problem. They will not kill the plant. Chemical control is not recommended in most home garden situations.
Keep Hydrangeas watered regularly during drought periods and avoid overhead watering to minimize wetness on the flowers and foliage. Clean up and dispose of symptomatic leaves at the end of the growing season.
Q: We have a steep hill that is covered with mature Japanese Pachysandra that is dying. It is under a large tulip tree. This groundcover was healthy for more than twenty years. During the last couple of years the leaves have turned yellow then the tips turn brown and curl up. The plant then dies. What is going on and how can we correct this problem?
This Japanese maple retained dried leaves during the winter. Photo: D. Ricigliano
Q: Most of my Japanese maples are still full of dead leaves. They never exfoliated in the fall to leave bare branches. Will this affect new growth in the spring? Should I just let them be?
A: We have received several questions about Japanese maples that are still holding on to brown leaves that didn’t drop last fall. Some crapemyrtles also have held their leaves during the winter. This issue has been reported in several areas of Maryland, which suggests it is due to an environmental factor. An unusually warm autumn followed by a quick cold snap likely interfered with the trees’ normal winter preparation processes.
As the days shorten in the fall, trees go through a series of biochemical and physical changes to prepare for winter survival. In deciduous trees, this includes the development of an abscission zone of cells where the branches connect to the base of leaf stems (petioles). A layer of cells essentially seals off the branches to protect them from water loss, and then the leaves are shed from the tree. We suspect the fall cold snap interrupted this process and normal leaf abscission did not occur in some trees.
Some types of trees naturally do tend to retain dead leaves during the winter. American beeches and many oaks exhibit this trait, called leaf marcescence. This occurs most often on juvenile trees. It may be a strategy to protect buds from winter damage or to discourage deer browsing. Trees may also wait until spring to shed their leaves, thus providing a fresh source of nutrient-rich organic matter to the root zone where soils are otherwise poor. The exact reasons for leaf marcesence haven’t been determined completely.
There is nothing you need to do for your Japanese maple at this time. If your tree was otherwise healthy, new growth will emerge in the spring and the old brown leaves will drop off eventually.
Q: My hydrangea bloomed white but instead of turning red it turned brown. What is happening to the petals and what can be done?
