Pruning


   “The grass on the rock, the flower of the heath, the thistle with its beard are the chief adornments of his landscape.” Ossian.

Well, here we are. 2017 has come to an end and 2018 lays before us. We are at the darkest time of the year as the winter solstice, which occurred on December 21st, brought us only 9 hours and 8 minutes of daylight on that day. That is 6 hours and 5 minutes less daylight than on June 21st! Its no wonder that this time of year is referred to as ‘hibernal’, a time when the deciduous trees are bare, the dropped leaves begin to decay, and birds and wildlife have settled into their winter homes and habits.

Squirrel on the suet feeder
A squirrel on the suet feeder      Image by S. Pelton

In Connecticut winter-time means that most plants have either died back or gone dormant. The evergreens hold onto their leaves and needles but they are not actively growing. Some of the more common evergreen landscaping plants for zone 6 such as the (clockwise from the top left) the rhododendron (Rhododendron sp.), the Eastern white pine (Pinus strobus), the mugo pine (Pinus mugo), and the white spruce (Picea glauca) add so much to the barren winter landscape.

                                                                                                Images by S. Pelton

The non-evergreen perennials can also be of interest during this time. From the top left clockwise, the American pussy willow (Salix discolor), the stonecrop (Sedum sp.), and the hydrangea (Hydrangea paniculata) all add some textual variety to the landscape.

                                                                                                         Images by S. Pelton

 

Their monotone appearance doesn’t really catch the eye like the very appropriately named winterberry (Ilex verticillata) does. One of the deciduous hollies, winterberry looks especially outstanding after a snowfall. As with most hollies the winterberry is dieocious and requires a male and a female plant to produce these beautiful red drupes which will remain on the plant through a good part of the winter to the benefit of small mammals and more than 40 species of birds.

                                                                                        Winterberry images by S. Pelton

But I would like to talk about an evergreen shrub that holds not only its leaves but its flowers all winter. Known as spring or winter heath (commonly but incorrectly called heather) Erica carnea has the most delicate, bell-shaped pink flowers and whorled, needle-like leaves that are barely ½” long. The family Ericaceae also includes the true heathers that were once included in the genus Erica but are now in the genus now called Calluna. Calluna heathers are called summer or autumn heathers and can be identified by their smaller, scale-like leaves which are in opposite pairs and their flowers which emerge in late summer. It is the heather Calluna vulgaris that evokes images of wide expanses of Scottish highland moors that appear to be covered in a pink mist.

5391978-PPTJohn M. Randall, The Nature Conservancy, Bugwood.org

It was the winter heath, Erica carnea, that stood out as I walked through our yard on a recent sunny but bitterly cold day. Its tiny pink flowers don’t seem capable of withstanding the arctic temperatures of the past week yet there they are.

heather in winter closeup 2                                                                                 Erica carnea close-up       Image by S. Pelton

The compact, or dwarf, size of most heath helps to limit the amount of air circulation through the plant and it creates its own microclimate whereby the plant is not as vulnerable to the cold as a taller, more openly branched plant. Its low growth habit does expose it to the possibility of frost when very cold air settles near the ground but it’s likely that in Connecticut a cover of snow may insulate it.

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                                                                                E. carnea in the snow    Image by S. Pelton

Early spring and early fall are the best times to plant, feed, or prune heath. When planting in full sun or slight shade in the early spring or fall do not allow these shallow rooted new plantings to dry out before they can establish themselves. Some gardeners amend the soil with peat moss, which can hold more than 20 times its dry weight in water in its cells, to help retain moisture. If you do add peat moss your heath plantings will receive an added benefit as the moss takes up calcium and magnesium from the surrounding soil and releases hydrogen. This action, called cation exchange, acidifies the soil. Heather prefers acidic soil which means that they are well suited to Connecticut. Plant them in area that will not be affected when you lime your lawn. Give them a dose of Holly-tone once a year when fertilizing other acid-loving plants such as rhododendron, azalea, or holly making sure that it doesn’t adhere to the foliage and reaches the drip line of the plant. As with any fertilizer it should be watered in.

                                                     Heath and heather images by the UConn Plant Database and S. Pelton

Spring is also good time to do any pruning of heath before the plant sets its flower buds or has new growth. Prune just to control any unwanted spreading and avoid pruning in the late fall as open cuts can collect water that will expand during a freeze and cause the stems to split. True heather (Calluna sp.) should be pruned annually in the spring as the flower buds do not set on old wood and the plants will become leggy and unattractive. Prune C. vulgaris at the base of old flowers.

Caliuna vulgaris heather

                                                                                   Calluna vulgaris      Image by S. Pelton

Other than needing occasional pruning heath and heather are very low-maintenance plants with few issues. You may find that deer or rabbits will feed on it as will the larvae of the Lepidopteran order which includes butterflies and moths or moths in the Coleophora genus. All in all, these plants are a wonderful addition to any yard or landscape as they unobtrusively add a swath of pink flowers and deep green foliage year-round. Perhaps 2018 is the year to add some year-round color to your landscape!

Susan Pelton

For additional information visit the UConn Plant Database: Calluna vulgaris (Scotch heather, Common heather) and Erica carnea (Spring heath, Winter heath)

Germander

Germander Plant, CQuish photo

Germander is an unusual perennial herb which makes a great edge of the border plant. Its Latin name is Teucrium chamaedrys. Germander takes well to shearing to form a garden border or knot garden, making it a good alternative to boxwood plants. Size of each plant will be about 10 inches tall with equal spread. It has also been used as a bonsai plant with great results.

germander hedge

Germander Border Edge, CQuish photo

 

Germander is native to Europe, Syria and the Greek Islands. It likes a pH of 6.3 and well-drained soil. Plant will produce pink blooms sporadically from mid-summer through the fall. Leaves have a strong unusual scent when crushed, and have traditional been harvested for medicinal properties to treat a variety of ailments in times before modern medicine. Although some folks still practice herbal remedies, we cannot recommend them in this forum as we are not doctors. Cut branches make a lovely wreath for decoration and freshen the air inside.

germander up close

Germander leaves close up. CQuish photo

Leaves are dark green, tiny and have serrated edges giving a fine overall texture to the plant. Germander is in the mint family, but behaves well in the garden, not spreading much. It also is not liked by deer due to its scent, and insects and diseases rarely attack adding to its attributes. Prune before new growth starts in the spring.

-Carol Quish

The Home & Garden Education Center has received an abundance of inquiries related to Japanese pachysandra, (Pachysandra terminalis) during the last few weeks. Homeowners all over Connecticut are experiencing difficulty with this groundcover. It first becomes noticeable as other things around it start to green up in the spring and we see that the leaves are remaining a sickly shade of yellowish-green.

pachy blight 2

Affected bed of pachysandra

As it catches our attention we notice that the plantings in general look a bit sad and sparse. A closer look at the leaves will reveal that there are areas of irregular brown blotches that have concentric line patterns within the affected area and pretty sharply defined darker brown edges. The center of the spots will can appear much lighter if the salmon-pink fungal spores are present.

pachy blight 1

Pachysandra leaves showing signs of Volutella blight

The browning areas will continue to spread and darken and can encompass the entire leaf as it dies. The cankers that can develop on the stems and stolons can girdle the stem and cause the plant to wither and die by disrupting the transport of water and minerals through the plants vascular system.Unfortunately this can happen in as little as two weeks, especially if the weather is wet and humid. It has certainly been wet over the last week and although the total precipitation is around the average 1” needed for growing plants it has come in a slow but steady sprinkle allowing plants little time to dry out between the showers.

This is all the work of the fungus called Volutella pachysandricola, or Volutella Leaf and Stem Blight. This fungus is considered an opportunistic pathogen that attacks weak plants. It can infect leaves, stems, and stolons and is considered the most destructive disease of pachysandra. The pink spores that appear in the spring will darken to reddish-orange in the late summer and fall when a second type of spore is produced.

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Close-ups of the Volutella damage and spores

This winter may have provided the perfect storm needed by Volutella to thrive. Drying winds and winter sun can desiccate pachysandra if there is not an adequate cover of snow to provide protection. Also, many beds of pachysandra are near roads and sidewalks where salts may dry them out further. A cover of mulch could provide just enough needed winter protection for plantings in these areas but it should be removed in the early spring. Some symptoms of winter injury or sunscald such as tan or scorched leaves may initially appear to be Volutella but they will not exhibit the characteristic concentric lines of the disease.

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Those same pachysandra beds that are near sidewalks or roads or are used as edgings can receive damage from mowers, clippers and weed whackers (Or as they are called in Australia, ‘whipper snippers’. I just love that!). Cuts from lawn equipment can provide an opening in plant tissue and when the plant is wet the fungal spores are able to infect it easily and travel to the stems where they will cause the girdling mentioned earlier.

Good sanitation practices can be helpful when dealing with pachysandra blight. It is too late for a good fall cleanup now but you can still remove any plant debris that remains. During dry weather remove and bag (not compost) any diseased plants to reduce the inoculum. Thinning out beds will also help improve the air circulation that can speed up drying. Fungicides can be used as preventives for new growth or when wounds occur and systemic curatives can be used when symptoms first appear although they will not correct damaged tissues. Allegheny pachysandra (Pachysandra procumbens) can be less susceptible to the disease or you could consider another groundcover such as creeping myrtle or vinca.

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Vinca major, also known as variegated greater periwinkle

Another source of wounds to pachysandra that should not be overlooked in insect damage. Scale insects such as Euonymous scale, two-spotted spider mites, and root knot nematodes have been found on plant samples that have come in to the Center. Horticultural oils and insecticidal soaps applied now can help control scale, just be sure to thoroughly coat the pests with the product. A miticide can be used on the spider mites but there is currently no control chemical treatment for the nematodes.

Euonymous scale

Euonymous scale image by Joan Allen

If you are experiencing these symptoms in your pachysandra beds you can get additional information from the Connecticut Agricultural Experiment Station fact sheet entitled Volutella Blight of Pachysandra, on our website at Pachysandra Leaf and Stem Blight, or by contacting us at the UConn Home & Garden Education Center.

-Susan Pelton

 

 

 

 

 

 

 

The very nature of herbaceous perennials is they die back to the ground, their roots and crown living through the winter. Perennials produce all new green growth each spring. They should  cut back by winter or, if the plant has interesting dried structure, left up for winter interest. Prune these in spring before new growth starts.

Pruning  perennials  during the growing season can have benefits. Plants will have more blooms and shorter plant will not flop over. Pruning encourages bushier plants compact plants and prevents leggy growth. Another positive outcome is delayed or staggering flowering. Buds can be removed causing the plants to regrow the buds. The time it takes to reproduce the flower material will cause the plants to bloom weeks later than they normally would. Exceptions to this rule are a few plants that will not create a new flower bud if it is cut off. Several perennials that should not be pruned before flowering  if their terminal bud is removed are iris, lilies, acanthus, astilbe, dictamnus, filipendula, geum, daylily, hosta, lupine and poppy.

Fall-blooming perennials can be pruned repeatedly, cutting back up to 1/3 of the plant starting when it reaches about 6″ tall. Repeat  every 2-3 weeks until July 4th. Let the plant grow for the rest of the summer to set its flower buds. Fall bloomers include chrysanthemum, sedum, and asters.

Phlox paniculata, UGA trial garden