In The Garden

In the Garden

Ralph Purkhiser, Purdue University Master Gardener

     Several people have asked me recently why their spring-flowering shrubs are blooming again.  The short answer to that question is that the plants are under stress.  That stress may be from extreme heat, drought, disease or even storm damage.  But why should stress cause a plant to bloom out of its normal season.  The answer to that is a bit more complicated.

     The primary purpose of all plants is to reproduce themselves.  For flowering plants, that is the reason for the flowers.  The flowers attract pollinators, which carry the pollen to other blooms and complete the process of pollination, eventually resulting in the production of seeds, which will fall to the earth and germinate, producing a new plant.

     When a plant is stressed, the need to reproduce becomes the highest priority.  That is the reason that stressed plants produce flowers, even if it is outside their normal bloom period.  Unfortunately, those out-of-season blooms rarely result in completing their mission and producing new plants.

     The good news is that most plants will recover from the stress that triggers re=blooming.  The key is to find the cause of the stress and do what you can to alleviate it.  If the stress has been caused by drought, water the plant regularly if there is not sufficient rain.  If the plant has been damaged, pruning out the damaged portions and allowing them to heal may help the plant recover.  If the cause is disease, determine the disease and research to see if there are ways to combat that problem.

     Certain plants are more prone to re-blooming.  Weigelas, for instance, set a major bloom in the spring, but often will sport a lesser number of blooms later in the summer.  Weigelas may actually bloom several times, and this phenomenon does not seem to adversely affect the next year’s blooms.  Lilacs also are prone to re-blooming.  Actually, there are some cultivars of oriental lilacs that have been bred to re-bloom.  Bloomerang lilacs may set blooms several times, with a fall bloom that nearly rivals the initial bloom in the spring.  The old-fashioned lilacs are especially susceptible to fungal diseases, and many people have noted that the leaves of the lilacs are turning brown and crisp.  There is not much one can do to fight a fungus, once it has started, but if the plant is otherwise healthy, it will survive and may set new leaves in a few weeks.  Do your best to clean up the old leaves and either burn them or dispose of them far away from the lilacs.  This will help reduce the danger of a repeat occurrence next year.  In worst-case scenarios, you may have to resort to a complete rejuvenation, cutting the shrub to the ground and cleaning up all of the debris.  If the roots are strong, the shrub will re-grow, but it may take a few years for it to bloom again.

     Encore azaleas came on the scene a few years ago.  These are plants that were bred to re-bloom.  Like the lilacs, the fall bloom period is usually lighter than the spring bloom.

     The most unusual re-blooming that I have noticed at Sandhill Gardens is on a China Girl blue holly.  The shrub bloomed well in the spring and has set abundant berries, which have started to get a little blush color on them.  I was looking forward to a good crop for wreath-making this Christmas season.  Recently, however, there have been some branches on which the leaves have turned brown, and the rest of the shrub is blooming again.  I suspect that heat stress has caused this problem, and the only thing I can do is make sure the shrub gets enough water and keep it as healthy as I can otherwise.

     Since there is little that we can do about re-blooming, the best advice I have is to enjoy the out-of-season blooms.  This may result in fewer blooms in the spring, but some fertilizer and good watering practices should help the plant get back on track.

• Garden

In the Garden

Ralph Purkhiser, Purdue University Master Gardener

     I just saw my first goldenrod blooms for the year, and right on time, my eyes are sticky and watering and my nose is running.  However, the two events are not really related.  It seems that I repeat this explanation annually, but I still hear people saying that the goldenrod gives them hay fever.

     To understand the situation, we must discuss the different ways plants are pollinated.  Some plants release their pollen into the air and depend on the wind to carry it and complete the pollination process.  In other plants, the pollen is carried from one plant to another by pollinators, including insects, birds and other animals.  It is those plants that release pollen into the air that cause hay fever symptoms in people.

     If a restaurant wants to attract people, the owners put up a sign.  Flashing neon signs get the attention of would-be diners.  Flowers play the same role in the realm of plants.  The flowers advertise the presence of nectar, and as pollinators stop in to eat, they get pollen on them, which they carry to the next flower they visit.  Such pollens are generally larger than those released into the air, and usually are a little sticky.  Since they are heavy and sticky, they are not released into the air and are not the cause of allergy symptoms.  In general, flowering plants do not cause hay fever!

     That being said, some people develop specific allergies that may be triggered by the scent of flowers, but such symptoms are specific sensitivities and not true hay fever allergies.  Some people also have tactile allergies to the sap of plants, usually resulting in skin rashes instead of hay fever symptoms.

      So why does the sighting of the bright yellow flowers of goldenrod signal the start of allergy season?  Is it all in our minds?  Not at all.  It is simply that goldenrod happens to bloom at the same time that ragweed blooms.  Ragweed flowers are tiny and green, so they are not showy and advertising for pollinators.  They release their pollens into the air and are the major cause of hay fever in the Midwest.  Another plant that is air-pollinated is corn.  When you see the tassels on the corn, you may find yourself having allergy symptoms.  Grasses and many weeds also release pollens into the air, and the beautiful goldenrod gets the blame, because it is more noticeable.

     The oft-maligned goldenrod is actually a beneficial plant for the eco-system.  In Indiana, there are more than twenty species in the genus Solidago, with one for just about every site.  Some tolerate dry soil, while others thrive in wet conditions.  Some are only about two feet tall, while others top out over six feet tall.  The flowers have many forms, but all have that beautiful bright yellow color to attract the pollinators.  The goldenrods are essential for late summer and fall pollinators, providing the energy needed for some to migrate and supplying the food that others need to get them through the winter months.

      As noted, the latex sap of Solidago may cause rashes for some people, but that latex has been investigated as a replacement for rubber, and research continues into other possible uses.

     Meanwhile, the flying pollen of common and giant ragweed continue to cause watery eyes, runny noses, scratchy throats and sneezing.  I encourage efforts to cut or pull those plants before they get to bloom stage.  It is not likely that we can get them all, but reducing the numbers will help keep the air clean.

• Agriculture / 4H

In the Garden

Ralph Purkhiser, Purdue University Master Gardener

      The steamy days of the last half of July may seem like a strange time to be talking about cool-season crops, but if you want to have a successful fall garden, now is the time to get started.  Just as one plants seeds in winter to have plants for summer crops, it is now time to plant seeds for fall crops.  Cabbage, broccoli and cauliflower may be planted now to grow transplants that will be set out in September and will mature in October and November.  These crops will withstand some frost and many people find that these vegetables taste better when they mature in cooler weather.

      There is still plenty of time to seed many other crops and the reasons to do so are many.  By planting a fall garden, you may find that you have avoided the life cycle of some of the major insect pests.  Imagine growing green beans without the presence of bean beetles.  Our early frost date is not until October 10, and in recent years, our first frost has come much later than that.  Look at the seed package and note the “days to maturity” statement.  If that number is below 90, then there is adequate growing season to get a crop.

     With root crops, the window is even larger.  Since the root is in the ground, and the ground remains warm long after the air begins to cool, root crops may often be harvested well into December.  My grandfather used to say, “Plant turnips on the twenty-fifth of July, wet or dry.”  There is a great incentive for planting turnips, even if they are not your favorite vegetable.  They may be grown either for the greens or for the root.  Even if left unharvested, turnips make a good green manure crop.  Just let them stay in the ground and till them up in the spring.  The roots help break up clay soil and the decaying turnip will add organic matter to the soil.

     Carrots and parsnips are also good fall crops.  Like the cole crops, the cool weather tends to sweeten these root crops.  In fact, many people say they do not like parsnips until they have gone through a freeze.  Radishes take fewer days to mature than most crops, and fall radishes tend to hold their crispness better than those planted in the spring.  There are even radishes that have been specifically bred for fall planting, and some of those “winter radishes” may be stored and enjoyed for months.

     Of course, the traditional fall garden crops are the salad greens.  Besides turnip greens, one may grow leaf lettuce, mustard, kale and most of those trendy oriental greens.  Just like with beans, note the number of days it takes to mature to see if there is enough growing season for the crop to mature.  Even if there is not enough time for a mature crop, you may plant most of the greens to harvest early as micro-greens.  If you have ever purchased micro-greens in the supermarket, you know that they command a hefty price.  For the price of a few packets of seeds, you will be rewarded with a lot of micro-greens.

     Fall planting is not just for vegetables.  There is still ample time for some annual flowers to mature to blooming stage.  I have been out pulling weeds and clearing some areas to throw out some of the zinnia and marigold seeds I have saved from last year.  I am planning a century celebration at Sandhill Gardens for late September, and those annuals should be blooming just in time.

• Agriculture / 4H
• Garden

In the Garden

Ralph Purkhiser, Purdue University Master Gardener

      Long-time readers know that my vacations always include visiting gardens, and my recent trip to Chattanooga, Tennessee with two great-nephews and a great-niece was no exception.  While the rental house in which we spent our week lacked any landscaping, we found several gardens to visit in the area.

     One of the must-see venues in Chattanooga is the aquarium.  That may not be a garden, but the aquarium actually has some interesting garden areas.  The attraction is divided into two portions, one being a river theme and the other concentrating on oceans.  While the river side has exhibits about the rivers of the world, a large portion deals with the ecosystem of the Tennessee River, which flows right by the aquarium.  Ecosystems involve the plant life along and in the water, and the exhibits showcased many native plants.

     Just down the street from the aquarium is the Discovery Center.  While not as lavish as the Indianapolis Children’s Museum, there was plenty to keep the children busy for several hours on a rainy day.  Again, plants play an important part in some of the inter-active exhibits.  A section on pollinators included the plants that attract and feed pollinators, including both native plants and other flowers and herbs.  There is also an exhibit promoting honeybees.  Again, the plants that supply the nectar from which the bees make honey were an important part of that exhibit.

     Also in the downtown river district is an area of several blocks known as the arts district.  The district includes several galleries and stores selling the work of area artists, but surrounding the stores and along the river are some beautiful gardens.  I was especially impressed with an area where American holly had been sculpted into tight hedges.  Interesting sculptures, both modern and traditional, are surrounded by gardens featuring both native plants and non-natives.  My personal favorite garden in the arts district was a vertical herb garden.  It was made by affixing a six-foot section of a hog panel between up-right four-by-fours.  Several troughs were fastened to the fence wires, and herbs had been planted in each trough.  It is something I would like to replicate here at Sandhill Gardens.

     Chattanooga and the towns in the suburbs have many parks, and there are several state parks near-by.  The parks afford opportunities to get out into nature, both on land and water.  It seems my car also automatically pulled into the lots of nurseries and garden centers, and I found an herb plant for which I have been searching.

     The area does have a noteworthy botanical garden.  That garden is found just over the Georgia border in Rock City.  The gardens included a lot of native shade plants, including oak-leaf hydrangeas, azaleas and laurels.  They also have made good use of some of my favorite shade plants, such as hostas and hellebores.  However, the star of the garden is the mountain itself, on which native stones have been used to construct amazing venues.  We crossed a swinging bridge to reach the famous look-out, from which portions of seven states may be seen.  Even a youngster who “does not like looking at plants” found this garden to be a fun place to visit.  The gift shop included many items to bring a memory home to the garden.  I chose a rain-chain windchime, but I regret that I did not purchase a birdhouse that looks like the barns where Rock City has been advertised for more than 80 years.

     Even the trip home brought a chance to view gardens.  I stopped in Nashville and took a couple of hours to visit the conservatories that make up the Opryland Hotel.  Although I have visited there many times, I never tire of experiencing the beauty of the gardens and man-made landscapes.