Presentation is loading. Please wait.

Presentation is loading. Please wait.

Invasive Plants from a Horticultural Perspective Mike Schnelle, OSU.

Similar presentations


Presentation on theme: "Invasive Plants from a Horticultural Perspective Mike Schnelle, OSU."— Presentation transcript:

1 Invasive Plants from a Horticultural Perspective Mike Schnelle, OSU

2 Please speak up as you have thoughts/questions during presentation Please speak up as you have thoughts/questions during presentation

3 Origins of Plant Materials Both native and non-native plants have value in the garden and landscape Both native and non-native plants have value in the garden and landscape Both native and non-native plants have pest resistance, not just natives Both native and non-native plants have pest resistance, not just natives Both will be discussed today Both will be discussed today

4 Start With Native Plants Growers and consumers could spend a lifetime just working with plants from the Lower 48. However, many ornamental characteristics and “looks” cannot be satisfied by our natives alone. Growers and consumers could spend a lifetime just working with plants from the Lower 48. However, many ornamental characteristics and “looks” cannot be satisfied by our natives alone. So when aesthetics and ornamental attributes are factored in, it is hard to overlook plants from other countries. So when aesthetics and ornamental attributes are factored in, it is hard to overlook plants from other countries.

5 Mexican Plum (Prunus mexicana) 12-15’ tree native to Mexico and much of U.S. including Kansas 12-15’ tree native to Mexico and much of U.S. including Kansas Grow for spring white flowers and sheer toughness of the tree Grow for spring white flowers and sheer toughness of the tree Heavy, wet soils will send this species into a mortality spiral – OKC Bombing Memorial Heavy, wet soils will send this species into a mortality spiral – OKC Bombing Memorial Some yellow fall color, attractive summer fruits Some yellow fall color, attractive summer fruits Seed propagation Seed propagation

6 Mexican Plum (Prunus mexicana)

7 Prunus mexicana Despite the name, Mexican plum IS native to many southern and central U.S. states Despite the name, Mexican plum IS native to many southern and central U.S. states

8 Serviceberry (Amelanchier) Greatly underutilized group of plants for Oklahoma and Southern locations Greatly underutilized group of plants for Oklahoma and Southern locations Better known and used north of us Better known and used north of us White flowers in spring White flowers in spring Pest-free summer foliage Pest-free summer foliage Yellow-orange-red fall color Yellow-orange-red fall color Showy edible fruits range from red-purple-black Showy edible fruits range from red-purple-black Growth habit varies from shrub to tree Growth habit varies from shrub to tree Many native to U.S. Many native to U.S. A crabapple alternative A crabapple alternative

9 Serviceberry (Amelanchier)

10 Non- native plants Appropriate when researched and used responsibly Appropriate when researched and used responsibly Pest advantage? Pest advantage? Traits not found in U.S. Traits not found in U.S.

11 Unsupervised Reproduction Happens with natives or exotics Happens with natives or exotics

12 Arguments Against Non-Natives May not serve as host plants for pollinators May not serve as host plants for pollinators May not be a significant food source for native fauna May not be a significant food source for native fauna May reproduce without human intervention May reproduce without human intervention Other Other

13 Invasive Plants A cultivated plant that under certain conditions will reproduce, unassisted by people, and ultimately displace native flora and occasionally native fauna A cultivated plant that under certain conditions will reproduce, unassisted by people, and ultimately displace native flora and occasionally native fauna No longer should we consider only exotic or introduced plants to be the only candidates. Natives in some instances could be invasive when moved out of their original U.S. range., Eastern redcedar for example. No longer should we consider only exotic or introduced plants to be the only candidates. Natives in some instances could be invasive when moved out of their original U.S. range., Eastern redcedar for example.

14 Challenges Most horticulturists want to continue to have the right to RESPONSIBLY introduce and grow plants of origins outside the U.S. Most horticulturists want to continue to have the right to RESPONSIBLY introduce and grow plants of origins outside the U.S. Invasive plants are a hot topic among diverse professionals. Invasive plants are a hot topic among diverse professionals. Horticulturists have different training backgrounds and “ornamental motives” than do ecologists for example. Horticulturists have different training backgrounds and “ornamental motives” than do ecologists for example. Communication and rational discussion amongst various disciplines is paramount in coming to agreements that all can live with. Communication and rational discussion amongst various disciplines is paramount in coming to agreements that all can live with.

15 Widespread Condemnation of Plants Because of the sheer size of the U.S., it is not logical nor appropriate to condemn any one species for cultivation anywhere in the continental U.S. Because of the sheer size of the U.S., it is not logical nor appropriate to condemn any one species for cultivation anywhere in the continental U.S. It is questionable whether any species exists that would prove problematic in all 48/49 states (Hawaii is the exception). It is questionable whether any species exists that would prove problematic in all 48/49 states (Hawaii is the exception).

16 Ornamentals that Bear Fruit Strong movement underway to discourage many female or otherwise fruiting plants in the landscape Strong movement underway to discourage many female or otherwise fruiting plants in the landscape The notion that a fruit-bearing plant will automatically be weedy IS NOT accurate The notion that a fruit-bearing plant will automatically be weedy IS NOT accurate Plants have to be screened/observed on an individual basis to determine their propensity to reproduce rampantly outside their intended area. Plants have to be screened/observed on an individual basis to determine their propensity to reproduce rampantly outside their intended area.

17

18

19

20

21 Tamarix

22 Pyrus

23 Ligustrum sinense ‘Wimbei’ (Chinese dwarf privet) This cultivar (also found as ‘Wimbish’) has been around for quite some time. However, it has taken me years to realize its value in the landscape! This cultivar (also found as ‘Wimbish’) has been around for quite some time. However, it has taken me years to realize its value in the landscape! Its diminutive size (4-7’), short internodes, variability from plant to plant really make for an exciting shrub, or extremely small “tree” in the landscape. Its diminutive size (4-7’), short internodes, variability from plant to plant really make for an exciting shrub, or extremely small “tree” in the landscape.

24 Chinese dwarf privet

25 Mimosa

26

27

28

29 Lantana In the lower 48, this species is normally harmless to the environment. In the lower 48, this species is normally harmless to the environment. Most breeders are working on fruitless types more for the reason of toxicity than for weediness Most breeders are working on fruitless types more for the reason of toxicity than for weediness However, if we lived in Hawaii, for example, lantana could be a major issue However, if we lived in Hawaii, for example, lantana could be a major issue

30 Breeding for Sterility Breeding for sterility, non-fruiting plant, should be encouraged however when flowers are the primary focus and the resulting fruits are known to be problematic. Breeding for sterility, non-fruiting plant, should be encouraged however when flowers are the primary focus and the resulting fruits are known to be problematic. Buddleia, for example, is currently being worked with to develop sterile new selections Buddleia, for example, is currently being worked with to develop sterile new selections

31 Euonymus alata Has reseeded in Eastern forest Has reseeded in Eastern forest Remains essentially innocuous to our environment here in Oklahoma Remains essentially innocuous to our environment here in Oklahoma

32 Ironwood (Parrotia persica)

33 Parrotia persica One of many exciting plants, from the Middle East, that so far are not proving to be invasive! One of many exciting plants, from the Middle East, that so far are not proving to be invasive!

34 What About Our Native Plants? Eastern redcedar and others are beyond the scope of today’s presentation. However, some experts have issues with this indigenous conifer and others. Osage orange, hackberry and other natives are now being watched largely because setting fires has been discouraged Eastern redcedar and others are beyond the scope of today’s presentation. However, some experts have issues with this indigenous conifer and others. Osage orange, hackberry and other natives are now being watched largely because setting fires has been discouraged

35 Commonly Grown Oklahoma Ornamentals That are Being Scrutinized Sawtooth oak (Quercus acutisiima) Sawtooth oak (Quercus acutisiima) Russian olive (Elaeagnus angustifolia) Russian olive (Elaeagnus angustifolia) Autumn olive (Elaeagnus umbellata) Autumn olive (Elaeagnus umbellata) Privet (Ligustrum ssp.) – all of them! Privet (Ligustrum ssp.) – all of them! Japanese barberry (Berberis thunbergii) Japanese barberry (Berberis thunbergii) Japanese spirea (Spiraea japonica) Japanese spirea (Spiraea japonica) Chinese/Japanese wisteria (W. sinensis/floribunda) Chinese/Japanese wisteria (W. sinensis/floribunda) Asian bittersweet (Celastrus orbiculatus) Asian bittersweet (Celastrus orbiculatus) Wintercreeper (Euonymus fortunei)_ Wintercreeper (Euonymus fortunei)_

36 Barberry a Problem in New England Again, most fruiting non-natives in OK are not problematic Again, most fruiting non-natives in OK are not problematic

37 More “Bad” Plants Periwinkle (Vinca minor) Periwinkle (Vinca minor) Porcelain berry (Ampelopsis brevipedunculata) Porcelain berry (Ampelopsis brevipedunculata) Japanese akebia (Akebia) Japanese akebia (Akebia) Ajuga (Ajuga reptans) Ajuga (Ajuga reptans) Saltcedar (Tamarix spp.) Saltcedar (Tamarix spp.) Beach vitex (Vitex rotundifolia) Beach vitex (Vitex rotundifolia) Many more as well as grasses and aquatics not discussed today! Many more as well as grasses and aquatics not discussed today!

38 Possible Solutions Horticulturists must implement screening processes before introducing new plants to the market. This would demonstrate our concern for the environment and in some cases squelch a small no. of plants from ever becoming widespread. Horticulturists must implement screening processes before introducing new plants to the market. This would demonstrate our concern for the environment and in some cases squelch a small no. of plants from ever becoming widespread. There may come a time when growers may want to consider voluntary stop sales on a few species. This has already transpired on the West Coast. For example, some people are no longer growing/selling Hedera helix (English ivy). There may come a time when growers may want to consider voluntary stop sales on a few species. This has already transpired on the West Coast. For example, some people are no longer growing/selling Hedera helix (English ivy).

39 Proposed Code of Ethics Do no harm to plant diversity and natural areas Do no harm to plant diversity and natural areas Perform risk assessments for introductions Perform risk assessments for introductions Remove invasives from plant collections Remove invasives from plant collections Control invasives in natural areas Control invasives in natural areas Develop noninvasive and native alternative plant material Develop noninvasive and native alternative plant material Do not distribute plants and seeds that will be invasive elsewhere Do not distribute plants and seeds that will be invasive elsewhere Educate the public Educate the public Become partners with conservation organizations Become partners with conservation organizations

40 Drought/Heat/Cold Up until about two years ago, many of us considered a number of our “staple” landscape plants to be essentially bullet- proof. However, given extreme drought, few record-cold nights and also record heat, some of these “bullet’proof” plants did indeed succumb or were badly damaged beyond aesthetically acceptable levels. Many of the best survivors are exotics! Up until about two years ago, many of us considered a number of our “staple” landscape plants to be essentially bullet- proof. However, given extreme drought, few record-cold nights and also record heat, some of these “bullet’proof” plants did indeed succumb or were badly damaged beyond aesthetically acceptable levels. Many of the best survivors are exotics!

41 Native vs. Exotic It is interesting to note that many of our affected plants were/are native to the U.S. and often including the State of Oklahoma. Still, even with their native origins we have all been reminded that all living organisms have limits to what they can survive! It is interesting to note that many of our affected plants were/are native to the U.S. and often including the State of Oklahoma. Still, even with their native origins we have all been reminded that all living organisms have limits to what they can survive!

42 One of the Few Unscathed Species from

43 Vitex (Vitex spp.) Genus as a whole taken for granted Genus as a whole taken for granted White, pink, purple or blue flowers on long spikes (for most spp.) White, pink, purple or blue flowers on long spikes (for most spp.) Marijuana-like foliage Marijuana-like foliage Can grow to be a tree sometimes to 20’ Can grow to be a tree sometimes to 20’ Normally winters will take it back down Normally winters will take it back down

44 Vitex

45 Aralia elata ‘Variegata’

46 Variegated aralia Has been scorned by most because it is coarse and considered too overwhelming with it’s color patterns Has been scorned by most because it is coarse and considered too overwhelming with it’s color patterns Should be used more – see Lendonwood Gardens or Sunshine Nursery for specimens to view Should be used more – see Lendonwood Gardens or Sunshine Nursery for specimens to view

47 Aralia spinosa (Devil’s walkingstick/Hercules club) Native Aralia sometimes goes unnoticed Native Aralia sometimes goes unnoticed Large shrub – often a small tree to 20’+ Large shrub – often a small tree to 20’+ Tropical looking leaves, white creamy flowers, club-like stems great for winter interest, purple black fruits Tropical looking leaves, white creamy flowers, club-like stems great for winter interest, purple black fruits Not a plant for the timid Not a plant for the timid I’ve grown weary of people rejecting this genus solely based on the presence of thorns I’ve grown weary of people rejecting this genus solely based on the presence of thorns

48 Staghorn sumac (Rhus typhina)

49 Tiger Eyes sumac

50

51 Rhus typhina Tiger Eyes

52 Don’t Lose Sight of Sheer Size of U.S.

53 Put Popular Articles Into Perspective

54 Prioritizing Invasives Work could be done between ornamentals industry and OkIPC to rank “biggest” offenders in order to have a realistic starting point. Work could be done between ornamentals industry and OkIPC to rank “biggest” offenders in order to have a realistic starting point.

55 Plants of Concern Ornamental pears (Pyrus spp.) Ornamental pears (Pyrus spp.) Privet (Ligustrum spp.) Privet (Ligustrum spp.) Honeysuckle (Lonicera spp.) Honeysuckle (Lonicera spp.) Tamarix (Tamarix spp.) Tamarix (Tamarix spp.) Russian olive (Elaeagnus angustifolia) Russian olive (Elaeagnus angustifolia) Other Other

56 Species of Less Concern Paper mulberry (Broussenetia papyrifera) Paper mulberry (Broussenetia papyrifera) Mimosa (Albizia julibrissin) Mimosa (Albizia julibrissin) Common mullein (Verbascum spp.) Common mullein (Verbascum spp.) Siberian elm (Ulmus pumila) Siberian elm (Ulmus pumila) Other Other

57 Planned “Talks” are Underway for 2013 I am hopeful that a representative of OkIPC will come to an ONLA board meeting yet this year to begin a dialogue. I am hopeful that a representative of OkIPC will come to an ONLA board meeting yet this year to begin a dialogue.

58

59 Summary 1) All of us desire the same end result in leaving the land as good or better than what we inherited. However, our approaches to doing so will differ. 1) All of us desire the same end result in leaving the land as good or better than what we inherited. However, our approaches to doing so will differ. 2) Many horticulturists will always desire to grow non-native plant materials in a responsible fashion of course. 2) Many horticulturists will always desire to grow non-native plant materials in a responsible fashion of course.

60 Summary (continued) 3) Plantspeople must continue to educate themselves about alternative plant materials, when warranted, that are safer to the environment, i.e. male selections, triploids, etc. 3) Plantspeople must continue to educate themselves about alternative plant materials, when warranted, that are safer to the environment, i.e. male selections, triploids, etc. 4) Solving or at least mitigating the invasives dilemma will necessitate a multidisciplinary approach meaning that horticulturists, ecologists, botanists, etc. come to the table and begin discussions 4) Solving or at least mitigating the invasives dilemma will necessitate a multidisciplinary approach meaning that horticulturists, ecologists, botanists, etc. come to the table and begin discussions

61 Summary (continued) 5) “Talks” will occur yet this year between OkIPC and the Oklahoma Nursery and Landscape Association (ONLA). This is a step in the right direction. 5) “Talks” will occur yet this year between OkIPC and the Oklahoma Nursery and Landscape Association (ONLA). This is a step in the right direction. 6) In the end, concessions and compromise will be required from all parties involved. 6) In the end, concessions and compromise will be required from all parties involved.

62

63 Thanks for Your Attention Questions? Questions?


Download ppt "Invasive Plants from a Horticultural Perspective Mike Schnelle, OSU."

Similar presentations


Ads by Google