In The Garden

In the Garden

Ralph Purkhiser, Purdue University Master Gardener

     Autumn will arrive on Sunday, September 22 at 8:44 AM Eastern Daylight Saving Time.  However, it appears that summer just does not want to let go.  Warm temperatures remain in the forecast.  A tropical system may bring some chance of much-needed rain to the Hoosier Hills this week, but cooler temperatures are not expected, with highs expected to be near 90 degrees.

     If you visit garden centers, you may see signs claiming that fall is for planting.  Normally, that is so, but the weather conditions need to be more fall-like to really be good for planting.  Perennials, trees and shrubs may all be planted in the fall, but timing is important.  For most plants, they need to be planted early enough to allow good root establishment before the ground freezes.  Without good root establishment, the plant may suffer from heaving during the freeze-thaw cycles typical of an Indiana winter.  It the roots are heaved out of the ground, they may freeze during the next cold snap.  Even if the cold does not kill the plant, the heaved roots will become desiccated if there is little snow cover.

     Moisture is another important factor in fall planting.  Soil moisture levels are low after several weeks of drought, and plants must have moisture to get established.  Supplemental watering will almost certainly be necessary, even if we get some rain.  Watering deeply is necessary.  Plants that are watered sparingly will develop feeder roots near the surface to take advantage of the water sprinkled on the soil surface.  Letting the water soak deep into the soil will make the roots grow to seek that moisture.  It is better to water deeply and less frequently.  On the other hand, some plants will suffer if we get a lot of moisture in the winter.  Such plants should be planted in areas with good drainage, such as on banks.

     Garden centers will soon be marking down the plants, and it is hard to pass up bargains, especially for plantaholics like me.  I already have a nursery area of plants I have purchased, and I am sure I will find more as I visit garden centers this fall.  The truth of the matter is most nurseries do not have the capacity to over-winter plants in pots.  While some plants that are especially cold hardy may survive, more marginal plants need to be in the ground.  Big-box stores do not overwinter any of their plants, so they will either discount them or throw them in the dumpsters.  However, a bargain is not truly a bargain if you are just going to let the plant die. 

     Plants set out in the fall will need special attention through the winter.  While our winters tend to be wet, if we do not get normal precipitation, you may need to water plants in the winter.  This should be done on days when the ground is not frozen.  You should check on your plants frequently to see if they need water.  You also need to watch for heaving of the root ball, and take steps to get the roots back in the soil if heaving occurs.  One way to prevent heaving is to apply a couple of inches of an organic mulch after the ground is frozen.  This will insulate the soil and keep it from thawing.

      Over the next couple of weeks, I will be trying to plant some of the shrubs and perennials I have purchased.  It will be a busy time, as I will also be preparing to host my Century Celebration open garden event on Saturday, September 28.  Come on by Sandhill Gardens to help celebrate 100 years of my family’s gardening here.  We will begin with a plant exchange at 10 AM, and there will be some gardening talks and demonstrations throughout the day.  It will be pretty informal, but I invite you to come and see plants that my maternal grandmother, Bertha Hooten, set out in the fall of 1924.  She must have done it right, as many of them are still growing in the same locations a century later.  I hope to see you here.

In the Garden

Ralph Purkhiser, Purdue University Master Gardener

     What are those yellow, daisy-shaped flowers growing along the roads?  This question has been posed to me many times, and there are many answers.  There are actually several different genera, each with multiple species that may have daisy-like yellow flowers.  Some are natives, and others were introduced and have naturalized.  The question of native or introduced sometimes gets pretty muddied.  Many native flowers were collected by early explorers and taken to Europe.  Some were bred to form new cultivars, which eventually made their way back to Indiana, where they escaped from cultivation.  These Nativars (cultivars of native plants) sometimes tend to out-compete the original species. Sometimes the native plants cross with the introduce plants, producing hybrids.  Even the experts argue if these plants are considered native or invasive.

     The easy answer to the question above would be to call all of them black-eyed Susans.  Indeed, that common name is often applied to such flowers, but is usually reserved for plants in the genus Rudbeckia, and most often to the particular species Rudbeckia hirta.  This common plant is a good example of a plant that has been the focus of breeding efforts, with several cultivars now existing.  It becomes difficult to determine the exact cultivar existing in a wild setting.  Rudbeckia fulgida is also native, but is rare in Indiana, and some varieties are considered endangered.

     The genus Helianthus is also common along Hoosier roadways.  There are many species, and this genus has long been the subject of breeding efforts to produce the sunflowers that provide food, oil and other products, and also to provide the many garden sunflowers popular as annual plants in flower beds.  We often see bees and other pollinators visiting plants of this genus, and their efforts result in many crosses.  The seeds drop or are carried by animals, resulting in many stands of sunflowers.  One particular native species that is presently in bloom is Helianthus tuberosa—the Jerusalem artichoke.  They have been called the intersection of flowers, food and foraging.  That common name is a big misnomer.  The species has nothing to do with Jerusalem and they are only very distantly related to the artichoke.  However, the tubers have been cultivated as a food crop for centuries by native peoples.  They were one of the earliest plants taken by explorers back to Europe, where they became popular for food and livestock feed.  In fact, the tuber was dubbed the greatest soup vegetable at a French food festival.  The tubers fell out of favor as a vegetable for many years, but have been making somewhat of a comeback.  They may be eaten cooked, raw or pickled, and are often touted as a low-carb alternative to potatoes.  They will propagate from seed or will re-grow from pieces of the tubers, so they often form dense colonies that are aggressive and will choke out competition.

     While there are numerous species of sunflowers, some of the similar-looking flowers belong to the      genus Heliopsis.  This genus is commonly known as false sunflower.

     The genus Silphium includes several species.  Prairie dock, cup plant, compass plant and various rosinweeds are included in this genus.  Most of them are tall plants with the flowers towering above some of the plant world’s most interesting foliage.  Many of the species are more common in marsh areas of northern Indiana, but the cup plant is common here in the south.  The leaves actually form cups along the stem, where rain may be caught and will persist for some time.  This plant is one that seems to attract the attention of visitors to my meadow.

     Other genera producing yellow daisies include Coreopsis, Helenium, Verbesina and Ratiba.  Many of these also exist in the meadow at Sandhill Gardens.  Come to the garden open house on September 28 to have a look at some of these plants.

• Garden

In the Garden

Ralph Purkhiser, Purdue University Master Gardener

     A truly great garden must appeal to all five senses.  The sense of hearing is probably the one least associated with gardening.  Many times, we resort to artificial means to add sound.  We hang wind chimes or set up a fountain to provide the sound of water splashing.  However, if we provide for the needs of nature’s musicians, they will come.  A recent visitor to Sandhill Gardens marveled at the sound of birds, frogs and insects.  Some creature is providing sound at almost any time of day or night.

     While the birds are still singing in the mornings, a major source of sound in the late summer garden is the hum of hummingbird wings and the buzz of bees.  With the intense heat recently, I have taken many breaks when gardening, and during those respites in the shade, I have enjoyed watching the ruby-throated hummingbirds flittering from flower to flower, providing a constant percussion.  The bees have also been busy, preparing for the coming of winter.

     While annual and perennial flowers provide feeding stations for the hummingbirds and bees, at this time of the year, a couple of shrubs are major sources of nectar.  Abelia and caryopteris are not native shrubs, but the constant presence of pollinators on their flowers in late summer and fall convince me that they deserve a spot in my landscape.  Neither has become invasive in Indiana.

     Abelia provides interest in all seasons.  There are about 30 species in the genus, many of which are at least semi-evergreen.  Even when not in bloom, the foliage is attractive and colorful.  The one at Sandhill Gardens has leaves that are green with accents of yellow, orange, bronze and burgundy.  The colors change with the season, becoming darker in the winter.  However, it is the tubular flowers that attract the bees and hummingbirds.  Abelia starts to flower in late spring, and, unlike most shrubs, continues to set new blooms into fall.  The buds are much darker than the open blossoms.  Since there are buds and blooms present together, the clusters take on a variegated appearance when viewed from afar.  My abelia has pink blooms, but there are species with white and yellow blossoms.  The black spruce and two large female blue hollies sited behind the abelia serve to make the shrub really stand out.  The bloom clusters make great fillers in bouquets, and will last several days as a cut flower.

     The blue of caryopteris makes a good foil for the pink abelia.  Commonly known as blue beard, this late summer bloomer also keeps blooming into late fall.  The steely blue is the color of the species, but there are cultivars with purple and white flowers.  The airy flower clusters are a great source of nectar, attracting native bees as well as honey bees.

     Both of these shrubs are low-maintenance plants, preferring sunny locations, but appreciating some shade in the hot afternoon.  Once established, they are very drought tolerant.  Neither of them has received any supplemental watering this summer, yet both are faring very well, despite the lack of rain.  They have few pest and disease problems and do not require a lot of pruning to keep them in shape.  If desired, the caryopteris may be cut to the ground in late winter and it will still grow to be a large shrub by late summer.

     Both of these shrubs may be propagated from cuttings or from seeds.  However, to ensure that they are true to the parent plant, it is better to use the cuttings.  Abelias may be produced from hardwood cuttings in the fall or from softwood cuttings in the spring.  Softwood cuttings root more easily, but plants produced from hardwood cuttings tend to be more hardy.  Caryopteris cuttings root easily and may be taken any time during the growing season.  Come out to the open garden at Sandhill Gardens on September 28 and take a cutting to grow you own shrubs.

In the Garden

Ralph Purkhiser, Purdue University Master Gardener

     Anyone who has been reading the column for very long knows that I am not big on turf lawns.  I certainly do not desire a golf course look for my lawn.  I actually love having clover, plantain and other broadleaf plants in my lawn.  However, I do like for the turf to be healthy enough to maintain some green color over the winter and to have enough grass to keep things from getting muddy.  Whatever type of lawn you desire, September may be the most important month for lawn care.

     Fertilizing your lawn in the fall is far more important than spring applications.  However, the fertilizer used at this time needs to be one with a higher third number, promoting good root growth.  Grass needs nitrogen, but at this time, the root growth is more needed than leaf growth.  Good roots will get your lawn through the winter.  Most lawn-care experts recommend fertilizing in September and again in late October or early November.  The lawn will keep growing, even after a frost, until the surface freezes.

     If you are looking for that perfect grass lawn, fall is also the time for applying a broadleaf herbicide.  Many common lawn weeds actually germinate in the late summer or early fall, then go dormant in the winter and re-awaken in the spring.  Such weeds will continue to absorb herbicides until frost.

      Fall is also a good time to plant a lawn, whether doing so to thicken an existing lawn or starting a lawn in a new place.  Your existing lawn may need more good turf grass.  Seeding into existing turf will help thicken a lawn.  I recommend aerating the lawn before planting.  The seed will make better soil contact with the slits left by aeration.  Another good method for over-seeding is to rent a power seeder that will power the seed into the soil.  Choose a quality grass seed.  Some seed companies have special blends for fall planting.  Once seeded, it is important that the lawn be watered frequently if rains are not sufficient.  When the new grass is about five inches tall, begin mowing to a 3-inch height and continue to mow until the lawn stops growing.

     The other fall lawn task has become a bit more controversial in recent years.  Most lawn-care professionals still recommend removing all of the leaves from a lawn.  Wet, matted leaves may smother turf if left over the winter.  However, many now recommend simply continuing to mow, chopping the leaves into small pieces that will decompose in place, adding organic material to the lawn.  As long as the leaf layer is not too thick, this mulching option seems to work well.  However, a lawn covered by thick, heavy leaves may need to be raked.  Instead of bagging the leaves, though, I recommend raking them into flower beds, where they will compost in place through the winter.

     At Sandhill Gardens, the late summer blossoms are beginning to shine.  The re-blooming azaleas are doing better than they have ever done.  Several patches of colchicums, also known as autumn crocuses, have peeked through this week.  Caryopteris, or blue beards, are near peak and the potentillas are full of blooms.  It looks like it will be a good late summer/early fall flower show.  Coming up on September 28, I will be hosting a Century Celebration at Sandhill Gardens.  My maternal grandparents moved to this place October 1, 1924, and several ornamental plants that my grandmother set out then are still thriving.  The celebration will not be fancy, but there will be a plant exchange beginning at 10 AM for anyone who wants to trade plants with other gardeners.  Fall is a good time to plant perennials.  I will have a fire in the fire pit if anyone wishers to bring hotdogs or marshmallows to roast.  Otherwise, just come and sit a while in the gardens or watch the sunset from the top of the cliff.  If you are in good shape, you may even want to walk down to the cave.  It really is a place of unique beauty.