Alternatives to Boxwoods. Ken Cote Indiana DNR, Division of Entomology and Plant Pathology

Size: px

Start display at page:

Download "Alternatives to Boxwoods. Ken Cote Indiana DNR, Division of Entomology and Plant Pathology"

Philippa Thomas
6 years ago
Views:

1 Alternatives to Boxwoods Ken Cote Indiana DNR, Division of Entomology and Plant Pathology

2 Overview Boxwood Blight Symptoms and Signs Boxwood Blight Survey Uses and forms of other plants How can you protect your nursery

3 What is Boxwood Blight Fungus Cylindrocladium psuedonaviculatum Warm Moist Conditions Temps 41-86⁰F, 77⁰F Optimum Above 91⁰F kills mycelia Microsclerotia are produced. Survive up to 5 years in leaf debris.

4 Where is boxwood Blight Confirmed cases in OH, PA, NY, VA, NC, MD, OR, CT, MA, RI Canada (BC, ON) Not yet found in Indiana.

5 Symptoms Plants develop small, black leaf spots Rapid progression symptoms resulting in leaf drop and small black stem cankers.

6 Infected plants on residential property Sharon Douglas, Connecticut Ag Experiment Station

7 Leaf Spots Sharon Douglas, Connecticut Ag Experiment Station

8 Blighted leaves, stem lesions, and defoliation. Sharon Douglas, Connecticut Ag Experiment Station

9 Black stem cankers and lesions Sharon Douglas, Connecticut Ag Experiment Station

10 Foliar symptoms: note leaf debris Sharon Douglas, Connecticut Ag Experiment Station

11 Infected boxwood and pachysandra Sharon Douglas, Connecticut Ag Experiment Station

Symptoms on pachysandra in landscape www.ct.

12 Symptoms on pachysandra in landscape Sharon Douglas, Connecticut Ag Experiment Station

13 Volutella Blight Looks Similar Melodie Putnam, 2008 Causes branch dieback Infects winter injured plants Both Boxwood Blight and Volutella can occur at same time Get lab results!

14 Boxwood Blight Survey 67 locations 34 Nursery Dealers 33 Certified Nurseries. No symptoms found out of 46,000 plus plants inspected Too hot for disease in 2012.

15 Boxwood Blight Counties Survey 2012

16 Boxwood Blight Survey Cultivars Found Green Mtn. Cranberry Creek North Starr Northern Charm Suffruticosa Chicagoland Green Baby Gem Gordo Golden Dream Franklin Gem Green Gem Green Borders Green Velvet Green Tower Variegated English Korean Rotundifolia Shadow Sentry Vadar Valley Winter Beauty Winter Gem Winter Green

17 Boxwood Blight Survey Boxwoods from: 13 states, 1 Canadian Province CA, IL,IN, KY, MI, OK, TN, and WI. Boxwoods found from: Connecticut, Maryland, Ohio, Oregon, Pennsylvania British Columbia, Canada This may pose a risk?

18 What if Boxwood Blight Gets Here? Sites will be managed under our clean plant laws. Landowners will be requested to follow best management practices to contain spread. Deep burial or burning. Protect adjacent, asymptomtic plants with fungicides. Fungicides are labeled for Cylindrocladium, more research is needed. Will we loose Boxwoods?

19 When Choosing Alternatives to Boxwood: Consider Plant Form Consider Plant Function Consider Plant Adaptability

20 PLANTS SIMILAR IN SHAPE

21 Inkberry Holly Ilex glabra Salt tolerant Adaptable to wet conditions High soil ph can lead to chlorosis Leaf drop can be a problem cv. Shamrock, Green Magic Southern red mite

22 Green Magic Inkberry Holly

23 Shamrock Inkberry Holly

24 Leaf Retention Issues

25 Japanese Holly Ilex crenata Best look alike Hardiness varies among cultivars Chlorosis in high ph soils cv. Convexa (very hardy) Green luster in photo

26 Uknown Cultivar of Japanese Holly

27 Chlorosis in high ph sutiations

28 Sky pencil: good replacement of Graham Blandy Boxwood

29 Ilex crenata Chesapeake

30 Dwarf Forms of Norway Spruce Picea abies Many forms available Highly adaptable Probably one of the better spruces for IN Mites can be a problem Bagworm

31 Picea abies Pumila

32 Dwarf Alberta Spruce Picea glauca Conica Slow growing rounded forms, conical forms Tolerant of shearing Topiary forms available in trade Less tolerant of shade and shearing than boxwood Spruce spider mite magnets

33 Other closely related forms

34 Blue Hollies Ilex x meserveae Fairly adaptable to Indiana soils Prefer acid, but doing okay at many unlikely locations Tolerant of shearing Especially cultivar China Girl or China Boy

35 China Girl Holly

36 Little Rascal Holly Ilex x Mondo Very low growing tight form I do not have a great deal of experience with this plant Seen winter injury in parking lot plantings

37 Globe Arborvitae Thuja occidentalis Cultivars Tiny Tim and Hetz Midget Slow growing forms that require little maintenance Mites and bagworm Drought injury in 2012

38 Mr. Bowling Ball Thuja occidentalis Bobazam

39 Yew cultivars Taxus sp. Many forms available May already be over used? Very tolerant of shearing and some shade tolerance Root rot and edema can be issues in wet soils

40 Boxleaf Euonymus Euonymus japonica Microphyllus Plant is similar in appearance May not be winter hardy in northern IN Scale, anthracnose and crown gall can be a problem Prefers well drained soil

41 Not Euonymus!

42 PLANTS FOR HEDGES AND PARTERRES

43 Bayberry Myrica pennsylvanica Coarser in texture Highly adaptable Tolerates shearing More ph adaptable than Inkberry holly Not reliably evergreen in Indiana May be ecotypes in trade

44 Bayberry Hedge

45 Stoloniferous

46 English Ivy Hedera helix Take sun or shade Can be sheared into many shapes Often gets twospotted spider mites when used in this manner Can be invasive

47 Lavendar Lanvendula cultivars Tolerant of shearing Cultivars like Hidcote and Munstead stay fairly low Probably more hardy than Grey Green Santolina Not that tolerant of wet soils Loved the 2012 summer

48 How Can I Protect My Nursery? Segregate boxwoods from states that have the blight Make sure nursery has been inspected for blight Hold plants for 4 weeks, inspect once a week for symptoms Place plants on landscape fabric so debris can be easily collected

49 How Can I Protect My Nursery? Obtain a fungicide history on boxwood imported to nursery from high risk states Avoid over head irrigation Maintain spacing for good air circulation Avoid pruning or working in wet plants Disinfect pruning shears and other tools with 70% ETOH, 10% Bleach, Lysol, Zero Tol or Green Shield.

50 How Can I Protect My Nursery? Disinfect all pots with 10% bleach before repotting boxwoods Do not compost dead boxwoods or bring boxwoods back to nursery cull piles Clean all tools and boots between job sites that have boxwoods Remember, there is an asymptomatic stage

51 What to do for suspect shipments Contact your DNR nursery inspector We will get laboratory confirmation for you Symptomatic plants, containers and associated soil need to be mitigated Asymptomatic plants will need to be treated with a fungicide and monitored

52 DNR Contact Information NO EXOTIC DNR Entomology Ken Cote

ARBORVITAE, MR. BOWLING BALL Thuja occidentalis Bobazam

ARBORVITAE, MR. BOWLING BALL Thuja occidentalis Bobazam ARBORVITAE, HETZ MIDGET Thuja occidentalis Hetz Midget Height: 2-3 Spread: 2-3 Color(s): green A dark green, slow growing, compact, globe shaped evergreen that maintains its shape without trimming. Water