This week we're in Charlotte, North, Carolina visiting The Duke Mansion.It's the middle of summer and the heat and doldrums of summer are takingtheir toll on our yards and gardens. The horticulturist at The Dukemansion, John Neville, utilizes some wonderful plants, has interestingtechniques for addressing summer problems and dealing with pests andpruning, all with the goal of "beating the heat."
John tells us that summers in Charlotte can be brutal. One of the majorfactors is the high humidity. High humidity for long periods of time,combined with temperatures of 90 degrees plus can do a lot of damage toplants. John feels the best thing he can do is study his plants, learntheir characteristics and grow plants accordingly.
John first shows us Hostas - Blue Hosta, Francis Williams. It is anestablished plant in a perfect area. English Laurel screens it from thewind, Oak trees protect it from the sun above, allowing it to receive alot of indirect sunlight. These plants are large and healthy. Once aplant like this gets to this size it pretty much takes care of itself.Selecting proper plants for your area and location, then getting thoseplants established is key to their success.
Plants in the summer get stressed. This is a function of water, pruning,weed and insect control. We look at a bed of Impatiens. Bed preparationis an important first step. John first tills the bed and adds good richcompost from the previous fall. With this in place he knows his plantswon't be bogged down in wet, soggy soil. Mornings are the best time towater, John uses a watering wand, watering underneath the plant. Hetries to stay away from the top of the plant because that may increasethe chance of fungus or disease. He tries to water before the dew hasfinished drying off in the morning, that way it doesn't extend the timethe leaves stay wet. He has mulch underneath, thus enough water mustpenetrate the mulch to ensure water will reach the root system. If yourplants are wilting during the day don't hesitate to water them at thattime, if water can be kept off the leaves that is preferable. The wandallows watering into a bed where one wouldn't typically be able to reachand makes it easier to get underneath the plant. Many ask - how muchwater is needed each week? That varies by plant and whether it is hot ordry, but in general one inch of water per week is good for flowers andturf. If watering by hand pull back the mulch and check out the soil.Dig down an inch or two, grab a handful of soil, squeeze it, if it staysclumped, that's a good indication that there is adequate moisture. Waterthoroughly yet infrequently, saturating the soil completely, then allowit to dry. Water must move down through the soil, encouraging the rootsto grow deeper into the ground. If watered every day the roots stayshallow, then if not watered the plants become unnecessarily stressed.
Hydrangea, Macrophylla typically likes filtered sun in the lateafternoon. This particular plant doesn't have filtered sun thus has atendency to wilt in the afternoon. This is called temporary wilt and iscommon with large leafed plants, especially where it is hot in themiddle of the day. Where there is heavy soil, water can't be taken upfast enough for the plant to transpire. With this type plant don't doanything. By the end of the day, when the sun is less hot, it will thenbe able to transpire and look ok. On the other hand, if by the nextmorning it is still dry, the plant is going into permanent wilt and itneeds water.
Newly planted or smaller plants may need watered more often, their rootsystems are small. It is difficult to over water plants during theirfirst month or two. In this case watering every day is ok, once theygain some size, once the roots become established, then water thoroughlybut infrequently.
A great garden should be cohesive. The different parts, the differentrooms should work together to create something that is greater than theparts. Hardscaping or paving material ties these areas together. In thiscase slate, placed close together, has been used to move through theturf and gardens. The slate is pressed down, it can be mowed across, yetit can still be used as a walkway. Using it protects the turf andprovides a hard path. The slate is also used in the patio. Here theslate is embedded in concrete providing a hard surface. The pathways andpatios tie together making an elegant, cohesive garden.
The Duke Mansion has a nice relationship or balance between formalelements like the sheared hedge and informal elements like the perennialborder. The hedge is Hoogendorn Holly and not Boxwood as many think. Itis different because it has a leaf stem arrangement that is alternativeinstead of opposite. John maintains a height of 2 to 2 and 1/2 feettall. John does his hard pruning in late winter, early spring. Thenthroughout the rest of the year he lightly prunes, if there is a limbsticking out he prunes that, leaving the rest untouched. It has a verynatural look. During the summer if the branches were to be removed itwould be stressful to a plant. We want to minimize the stress and thebest way to do that is to prune when the plant is dormant. February is agood time for pruning, at that time the plant has lots of stored energyand can use that energy to have a nice flush in the spring. This time ofyear the plant is growing, by removing large amounts of foliage it wouldtake a long time for the plant to recover. It probably wouldn't kill anestablished plant but would bother the plant and would make it moresusceptible to fungus and diseases.
Many gardeners prune by shearing, taking the tops off. A more plantfriendly approach is to thin the plant. First remember that maintainingthe height is most important, the objective shouldn't be to make iteven, instead keep it informal looking. To do this, select branches thatare not symmetrical with the plant itself, reach deep into the plant andcut those branches closer to the base. Be careful not to create big gapsor holes that look unsightly. Sunlight will hit the cleared area,rejuvenating the tissues and forcing more branching to emerge. Removeonly at most one third of the branches throughout the entire plant. Itwill open it up for a month or so, but by allowing sunlight deep intothe plant, growth will be encouraged.
It's not unusual to see winter damage on plants. Wait until plants arefully flushed out before making a decision whether a limb will comeback. Sometimes limbs are slightly damaged or stressed and they take alittle bit longer to come back. About June take a hard look and pruneall dead wood, if it hasn't branched out by then it probably won't.Another way to determine where to prune is to scratch the bark, if itisn't green that means that part is probably dead. Follow the branch allthe way down, if it is still brown that's an indication it's dead, if soprune it out. If a branch is dead at the tips, but has foliage furtherdown, prune the tips. Don't cut into the green growth. Cut above thegreen area at an angle. After pruning give the plant plenty of water andadd slow release fertilizer. That will help stimulate the roots whichthen provides a flush of growth.
During the summer insects become a problem. John always inspects plantsbefore buying them. Sticky strips are good for indicating insectinfestation problems. By placing them around your plants one candetermine what insects are present. The strips act like a monitor, theydon't get rid of the problem, they just alert us to the insectsthemselves, letting us know they are there. If a population is heavyJohn might first use insecticidal soap. If that doesn't work afterseveral treatments it may be necessary to use a chemical to get rid ofthem.
White Fly can be a problem, they are only about 1/8 of an inch long andonly fly if the plant is rattled. Insecticidal soap tends to coat theirbody and dissolves their exoskeleton. If this doesn't work a systemicinsecticide is needed. The insecticide goes inside the plant and becausethe White Fly has sucking mouth parts, it ingests the insecticide andrids the plant of the pests in this manner. A contact insecticide, asystemic insecticide seems to work very well. It shouldn't be used onplants that would be eaten or harvested.
We've received many emails asking "who's been spitting on my plants?"This is the work of a Spittle Bug. It is a sucking insect but really aharmless insect, thus it isn't necessary to use chemicals. If one wantsto get rid of these insects use a stream of water on sturdy plants ortrees, if on a more fragile plant a jet of water could damage it,instead wash them off.
A bug that does a lot of damage and is microscopic is the Thrip. Ifpetals are malformed or if leaves are deformed that is an indication ofThrip damage. They have rasping mouth parts, something like sandpaper.Thrips get down into the plant and scrape against the leaf or tissue,the nutrients or sap come out, the Thrip laps it up and that is how theyfeed. Insecticidal soaps, Orthene or Malithion work well to get rid ofthese critters. John uses these products on Coreopsis, Day Lilies andsome Roses. Try to detect the problem early. To do that take a bud andpeel it back, if a lot of little insects scurry around, then address theproblem.
Black Spot can be a problem and Red Tip Phoetenia is susceptible. Thefirst stage is a darkened spot, it then turns gray which results in thetotal branch dying back. A general fungicide will keep it at bay. It maybe necessary to thin shrubs if too thick, allowing for more aircirculation. Black spot isn't much of a problem in dry areas, humidareas pose more of a problem. If a plant has the disease take the deadleaves and remove them, if possible burn them. The best strategy is toselect plants not susceptible to Black Spot in your area.
We expect Annuals to look great from spring till fall. That is achallenge because they exhaust themselves by mid to late summer. Don'tbe afraid to give them food, fertilize them, throughout the entireseason. That way they'll look great spring through fall.
John tries to enhance the property with bright yellows, hot reds andpinks. This brings the guests out of the house and into the gardens.This is made easier if the color is close to the house. One particularlypretty plant is Mellopodium, Derby. It is drought resistant, has fewinsect problems and it reseeds prolifically. This variety doesn't needto be deadheaded, they self-clean. They put out vigorous shoots andbloom throughout the summer. It likes full sun and thrives in the heat.This garden is bordered with Ageratum, Blue Danube. It compliments thecolor of the Mellopodium. It too likes the heat, the dryness and as longas everything stays evenly moist, thrives and stays compact.
Floss Flower has floss-like petals that are delicate and very soft. NewGuinea Impatiens are an impact plant, very bold. Make sure the soil iswarm when planting and provide adequate moisture. They are heavy feedersthus like a slow release fertilizer. The flowers are big and florescent,the plant will grow to about 2 feet tall. Behind them are Caladiums,variety White Queen. Its' growing requirements are similar to theImpatiens - good, heavy feeders, ample moisture and most take filteredsun. This bed has a nice combination of plants that work well togetherand all have the same needs or requirements. John feels it is importantto select plants that will thrive in the middle of summer.
John chose Zinnias, this variety is Dreamland because they are bushy.Zinnias are susceptible to Powdery Mildew, thus it is best to try tokeep water off their leaves. The best way to do that is to waterunderneath the leaves. There are a lot of different colors available inthis series, all have the same habit and same plant form. The color isthe difference.
John the garden looks great, even in the middle of the summer. You'vedone a masterful job of handling the weeds, the watering, all the summerproblems. Thanks for showing us the gardens at The Duke Mansion.
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