~1

ARNOLDIA

A continuation of theBULLETIN OF POPULAR INFORMATION

of the Arnold Arboretum, Harvard University

VOLUME 10 JUNE 16, 1950 NUMBERS 7-8

ORDER OF BLOOM

ALTHOUGH the actual dates on which certain plants bloom will vary fromyear to year, the sequence will remain the same. Lilacs will always beginto flower a little after some of the crab apples have reached their peak ; mostof the rhododendrons will follow the lilacs, and the mock oranges will follow therhododendrons. Records of the sequence and the time of bloom of the many

flowering trees and shrubs in the Arnold Arboretum have been kept over a longperiod of years and in the following lists some of them are recorded in their

sequence and in the approximate time when they can be expected to flower

normally.It should be stressed that some shrubs especially those with double flowers

will remain in flower longer than others and hence can be used effectively in

gardens with plants that are noted as blooming later. Still others are effective in

flower bud and might be planted with varieties blooming earlier. Local studies

along this line should prove most interesting to individual gardeners.In this connection it might be of interest to note the different times at which

Cornu.s florida blooms throughout the country. This tree has a wide habitat o~ erthe eastern United States and is so beautiful that it ~s highly valued as an orna-mental wherever it is bud hardy. It can be expected to bloom in the followingplaces at the approximate times mentioned.

Glen St. Mary, Florida

Augusta, GeorgiaSt. Louis, MissouriAshville, North CarolinaWashington, D.C.

Lexington, KentuckyColumbus, Ohio

Nlid-Februar~~Late MarchEarly AprilMid-AprilLate April« ..

Early May

41~

Philadelphia, PennsylvaniaLondon, EnglandChicago, IllinoisDetroit, MichiganRochester, New YorkBoston, MassachusettsSeattle, WashingtonPortland, Maine

Early May.< «

Mid-May«

« <

« 4

«

Late May

One other series of dates has proved interesting at the Arnold Arboretum.There is a weeping willow tree adjacent to the Administration Building whichturns green almost over night when the weather is just right. Since the bud

scales of willows are valvate, the bud scales drop when the temperatures are highenough and the young foliage quickly swells and gives the tree a green appear-ance. Since this happens rapidly-almost overnight-the dates on which thisoccurs afford a valuable commentary on the earliness or lateness of the season.

The following are the dates for the past eleven years.

The following order of bloom is applicable in localities other than New Eng-land. If local blooming dates of a few key plants are noted and the differenceschecked with those given in the following sequence, then all the dates can be

correspondingly shifted and the sequence can thus be adapted to local climatic

conditions.Order of Bloom

(All plants in the following lists are growing in the Arnold Arboretum underpractically the same soil and climatic conditions and have bloomed together inthe following sequence.)

February ~ March

Hamamelis vernalis Acer saccharinum

43

Corylus speciesHamamelis japonica

"

mollis

Sahx speciesSnowdrop and Crocus

Early April

Acer rubrum

Alnus incana""

rugosa

Cornus mas"

officinalis

Daphne mezereumErica carnea

Forsythia ovataJasminum nudiflorum

Lonicera praeflorensPopulus speciesPrunus davidiana

Ulmus americana

Viburnum fragrans

Mid-April

Abeliophyllum distichumAcer negundoBetula speciesCercidiphyllum japonicumCorylopsis speciesDirca palustrisEpigaea repensForsythia europaea

"

intermedia varieties"

suspensa sieboldi"

viridissima

Lindera benzoin

Lonicera fragrantissima"

purpusi"

standishi

Pieris japonicaRhododendron dauricum

"

mucronulatum

Shepherdia argentea

, Late April

Acer circinatum"

diabolicum purpurascens"

platanoidesAmelanchier canadensis

"

laevis"

spicataBuxus microphyllaChamaedaphne calyculataEuptelea polyandraLonicera altmanni pilosiuscula

66

tenuipesMagnolia denudata

"

kobus"

borealis"

salicifolia"

stellata

Malus baccata mandshurica

Myrica galePieris floribunda

Poncirus trifoliata

Prunus armeniaca""

canescens"

cerasifera"

concinna"

cvclamina a"

dasycarpa"

domestica"

incisa and varieties"

juddi"

mandshurica"

nipponica"

sargenti"

subhirtella and varieties41

tomentosa"

triloba"

yedoensisSpiraea prunifoliaVinca minor and varieties

Early May

Acer campestre .

PLATE X

Viburnum tomentosum mariesi. This variety has larger flowers and fruits than thecommonly grown Doublefile Viburnum (T : tomentosum).

45

Acer saccharum

Amelanchier grandiflora"

humilis" ."

sanguinea"

stolonifera

Andromeda glaucophy-lla"

polifoliaBerberis dictyophyllaCarpinus carolimana

’

Chaenomeles japomca and varieties"

lagenaria and varietiesCrataegus arnoldianaCytisus decumbens’ "

elongatus"

beani

Dandelion

Enkianthus perulatusExochorda giraldiLedum groenlandicumLonicera canadensis

C‘

coerulea""

saccata

Magnolia soulangeana and varietiesMahonia speciesMalus adstrmgens and varieties

‘‘C

arnoldiana"

astracanica46

atrosanguinea"

baccata"

brevipes"

floribunda ’

"

halliana and varieties"

hupehensis"

micromalus"

prunifolia and varieties"

pumila niedzwetzkana"

purpurea and varieties"

robusta and varieties"

scheidecl;er~"

soulardi"

spectabilis and varieties"

sylvestris

Malus zumi and varieties

Myrica pensylvanicaNarcissus

Bemophanthus mucronatusOrixa japonicaOsmaronia cerasiformis

Pachysandra terminalisPhlox subulata

Primula elatior superba"

polyanthaPrinsepia sinensisPrunus alleghaniensis

" ,

11

americana"

avium"

blireiana and varieties ,

"

glandulosa and varieties"

hortulana"

incana"

instititia"

japonica nakai"

maritima"

padus and varieties"

pensylvanica"

persica and varieties e,"

pumila susquehanae !

"

serrulata and varieties

(Many double-flowered forms start-ing to bloom and continuing for twoweeks at least, depending on thevariety, some being slightly earlierthan others.)

Prunus sieboldi

Pyrus communis and varietiesRhododendron mucronatum

"

venustum

Rhus aromatica

Ribes alpinum""

aureum"

gordonianum ,

"

odoratum

Spiraea arguta"

thunbergi

46

Syringa hyacinthiflora and varieties"

oblata dilatata ‘

TulipsViburnum alnifolium

" 6

buddleifolium"

burejaeticumViolets

Xanthorhiza simplicissimaZanthoxylum amencanum

Mid-May

Acer palmatumAesculus arguta

"

bushi""

carnea"

glabra"

hippocastanum"

neglectaAkebia quinata

" tnfoliata

Alyssum gemonense"

saxatile

Amelanchier amabilis

Amelasorbus jackiAristolochia manshuriensis

Berberis dielsiana"

julianae"

koreana"

stenophylla"

thunbergi and varieties""

vernae"

vulgarisCalycanthus floriclusCaragana arborescens

"

frutex"

sophoraefoliaCercis canadensis

"

chinensis

Cornus florida

Cydonia oblongaCytisus praecox

" 6"

purgans

Cytisus purpureus61

scopariusDaphne altaica

6 1

caueasica""

eneorum

Deutzia grand itiora .

Uavidia involucrata

Elaeagnus multiflora46

umbellata

Enkianthus campanulatusEuonymus alata

11

latifolia

Exochorda korolkowi,.

macrantha""

racemosa

Fothergilla species ’

Halesia carolina6 6

monticola

Iberis tenoreana

Kerria japonicaLeitneria floridana

Lonicera alpigena66

bella a66

chrysantha6 6

muendeniensisig

muscaviensis14

syringantha66 11

wolfi46

thibetica66

xylosteumMagnolia fraseri

16

lihflora nigraMalus bracteata .

"

glaucescens"

ioensis"

sargenti"

sieboldi and varieties

Papaver orientalePaulownia tomentosa ’

Prinsepia unifloraPrunus cerasus

"

maacki

;;:.

.."

"ê

~G

’a0a..0::s

x

Hic

a~wII)... .-!

~ ’"

¡.¡ .;!:H ~a ~~a, ~

’"U

N8

<:N

yeCG

II)Y~

CO

~

U~~.~V

48

Prunus virginiana _

Quercus speciesRhododendron albrechti

41

eanadenseit

carolinianumis

fraseriit

luteum .

is

obtusum amoenumis 64

arnoldianum46

Hmodegtr)’ " "

japonicum"

. "kaempferi"

racemosum"

reticulatum"

schlippenbachi« ."

vaseyi"

yedoense"

64 poukhanenseRhodotypos scandensRibes sanguineumSambucus pubensSibiraea laevigataSorbus aucupariaSpiraea cinerea

"

gemmata44

hypericifolia44

inflexa"

media ’

, ,

mollifolia"

oxyodon"

pikoviensis"

prunifolia plena"

pubescensSyringa vulgaris and varieties

(With over 300 varieties, it is im-

possible to list them here as early,medium and late, although somemight be so listed.)

Vaccinium angustifolium laevifoliumViburnum bitchiuense

44

burkwoodi"

carlesi

Viburnum juddi«

lantana

Weigela "Conquerant"« ‘<F,leur de D~a~"" "Floreal"«

florida venusta« "Gracieux"

Wisteria venusta and varieties

Late May

Acer ginnalaAronia arbutifolia

"

melanocarpa«

prunifoliaAsimina triloba

Berberis arnurensis«

circumserrata«

o~adnepaini«

verruculosa

Berchemia racemosa

ButtercupCaragana maximowiczianaCelastrus flagellaris

«

orbiculata<‘

scandens

Cornus alternifolia6 6

controversa"

stolonifera

Coronilla emeroides

Cotoneaster adpressa«

apiculata«

divaricata«

foveolata<‘

nitens«

racemiflora

Crataegus crus-galli"

oxyacrantha«

‘< pauli«

pruinosa"

punctata«

succulenta

Daphne giraldi

>.s-

sro~Ec

800~

)-~ ~1~· yIV ^rW t~ II)

N ~<!* 4)

~^4 ~~Y

G7

..c:1~

_~OU’§O¡;I:ja X’-H

[~o_

DayliliesDeutzia candelabrum

"

gracilis"

kalmiaeflora"

lemoinei and varieties"

rosea and varieties

Dipelta floribundaEnkianthus deflexus

"

subsessilis

Fendlera wrightiFontanesia fortunei

Gaylussacia baccataGenista pilosaIberis sempervirens

’

Juglans sieboldianaLaburnum speciesLeucothoe racemosa

Lonicera amoena"

korolkowi"

maacki"

maximowiczi sachalinensis"

morrowi"

tatarica and varieties

Magnolia cordata"

soulangeana lennei"

tripetala"

virginiana"

watsoni

Malus angustifolia"

coronaria" "

charlottae" ioensis plena"

toringoidesNeillia sinensis

Paeonia suffruticosa

Petteria ramentacea

Philadelphus hirsutus"

schrenki jackiPhotinia villosa

Physocarpus amurensis""

monogynus

Potentilla fruticosa and varieties

Prunus laurocerasus schipkaensis" <

serotina

Rhamnus cathartica

Rhododendron atlanticum"

catawbiense "Boulede Neige"

Rhododendron catawbiense "CharlesDickens"

Rhododendron catawbiense "MontBlanc"

Rhododendron fortunei "Duke ofYork"

Rhododendron gandavense hybrids"

japonicum"

molle hybrids"

nudiflorum""

roseum"

smirnowi

Robinia elliotti"

fertilis"

kelseyi"

slavini

Rosa ecae"

hugonis"

primula" xanthina a

Rubus deliciosus

Schisandra chinensis

Smilax rotundifolia

Spiraea blumei"

cantoniensis"

multiflora"

nipponica" rotundifolia"

trilobata"

vanhouttei

Staphylea colchica"

trifolia

Symplocus paniculataSyringa chinensis

"

julianae"

meyeri

51

Syringa microphylla"

persica"

pinetorum"

potanini"

pubescens"

velutina‘ ‘

wolfi" ."

yunnanensisTamartx parvifloraThymus serpyllumVaccinium corymbosumViburnum lentago

"

macrocephalum sterile"

opulus roseum"

rafinesquianum"

rhytidophyllum"

rufidulum"

sieboldi i"

tomentosum" "

sterile"

trilobum"

wrightiWeigela "Dame Blanche"

"

"Lavallei"Wisteria floribunda and varieties

"

formosa"

sinensis and varieties

Early June

Abelia englerianaActinidia argutaBuddleia alternifolia

Ceanothus ovatus

Chionanthus retusus"

virginicusCladrastis lutea

Cornus alba"

kousa""

rugosa

Cotinus coggygriaDaphne ponticaDecaisnea fargesi

Elaeagnus angustifoliaEuonymus atropurpurea

"

bungeanaGenista hispanica

"

tinctoria

Halimodendron halodendron

Helianthemum nummularmm

Hydrangea petiolaris"

xanthoneura wilsoni

Idesia polycarpaIlex opaca

Indigofera amblyanthaJamesia americana

’

Kolkwitzia amabilis

Leucothoe catesbaei

Lonicera ruprechtianaMagnolia sieboldiPeriploca graeca

" .

6 6

sepiumPhellodendron amurense

Philadelphus "Banniere""

.11

caucasicus"

" Cole’s Glorious""

" Conquete"" ,"

coronarius"

"Coupe d’Argent""

floridus"

laxus"

magdalenae" Manteau de Hermine""

maximus"

nepalensis -

"

pekmensis"

" Rosace" <

"

tomentosus

Physocarpus intermedius"

opulifoliusRhamnus davurica

"

frangulaRhododendron arbutifolium

"

calendulaceum"

catawbiense and vars.

.7~

Rhododendron ferrugineum44

laetevirens66

minus41 "Mrs. C. S. Sargent""

"Purpureum Grandi-florum"

RhuspotaniniRobiniahartwigi

14

hispidaIt

pseudoacaciaRosa acicularis

arnoldiana -

"

bella

blandafoetida bicolor46

harisoni

I’heritieranaroxburghirubrifoliarugosa and varietiesspinosissima and varieties44 N%,ilimottiae

Sassafras albidum

Sophora viciifoliaSpiraea blanda

46

chamaedryfolia46

henryi46

trichocarpa44

wilsoni

Staphylea pinnataStyrax americana

"

.japontea"

obassia

Syrmga henryi and varieties11

josikaea and varieties"

komarowi"

prestoniae and varieties..

renexa.

"

swegmzOBB’J"

tomentelia"

x,illosa

Vaccinillm stamineum

Viburnum cassinoides"

dentatum"

dilatatum and varieties"

hupehense"

lobophyllum"

opulus"

prunifolium"

sargentiWeigela florida

"

" Gratissima"Wisteria macrostachva

Mid-June

Amorpha fruticosa"

glabraCastanea pumilaCatalpa speciosaCeanothus americanus

Cornus amomum"

bretschneideri""

coreana""

racemosa

Cotinus americanus

Cotoneaster dielsiana"

horizontalis"

multiflora

Crataegus phaenopyrumDeutzia "Contraste"

" 6

"Magicien""

magnificaDiospyros virginianaEuonymus europaea

"

fortunei vegetaGymnocladus dioicusHydrangea bretschneideriIlex glabra"

verticillata

Indigofera decora.‘

kirilowi.

"

potaniniKalmia angustifolia

"

latifolia

EayN0Fv

t)

~G

~G7a0apW. bc.

X =3~! 0 ~t

a~CLt ~

v

C~

a~h

<u

x1~d

V§O’~~._~~

54

Ligustrum amurense"

ibolium«

i bota ’

" obtusifolium

" 6 4

regelianum"

ovalifolium"

vulgareLiriodendron tulipiferaLonicerabrowni

6 6

iberica14

japonica halliana66

periclymenumL yonia ligustrina

44

mariana

Philadelphus "Albatre""

66 Argentine" .

46 Atlas44 46 Avalanche""

66 Bouquet Blanc"66

46 Boule d’Argent"""

cymosus" Girandole"66 "Glacier""

grandiflorus" Innocence""

inodorus"

lemoinei and varieties"

microphyllus"

monstrosus" "Mont Blanc"if 64 Norma"" 64 Pavillon Blanc""

pubescens"

purpurascens"

splendens"

zeyhei-iPyracantha coccinea lalandi

’

Rhododendron Album Elegans"66 66 Grandiflorum"66

arborescens

Robinia B’iscosa

Rosa alba

Rosaarvensis"

canina..

centifolia

" damascena..

davidi .

..

eglanteria"

g’a II ica., helen8e

jacksoni6

micrantha4

moyesi.. multiflora" " 6

cathayensis"

virginiana..

webbiana

Rubus allegheniensisSambucus nigraSpiraea veitchi

"

watsoniana

Stephanandra incisaSymphoricarpos albus laevigatusSyringa amurensis

ft t < .." "

japonica..

pekinensisTilia platyphyllosViburnum acerifolium

66

molle66

pubescensWeigela "Congo"

4 1 "Eve Rathke"Zenobia pulverulenta

Late June

Acanthopanax sieboldianusActinidia polygamaAilanthus altissima

Ceanothus pallidus roseusCornus m8crophyllaCotoneaster salicifolia

Deutzia myriantha..

scabra plena..

staminea

55 ~ ]

Diervilla sessilifolia

Dorcynium hirsutumGenista anglicaIlex crenata

Indigofera incarnata albaItea virginicaLavandula officinalis

Lonicera henryi1’Itiladelphus "Belle Etoile"

"

burkwoodi" "Enchantment""

virginalis and varietiesRhododendron maximum

Rhus typhinaRosa multibracteata

Sambucus canadensis

Schizophragma hydrangeoidesSorbaria sorbifolia

Spiraea b~lliardt"

bumalda and varieties"

douglasi"

japonica"

latifolia"

margaritae"

menziesi"

pyramidata"

tomentosa"

virginianaStephanandra tanakaeTripterygium regeli

Early July

Buddleia japonicaCallicarpa dichotoma

"

japonicaCytisus nigricansHolodiscus discolor

Hydrangea arborescens"

grandifloraHypericum kalmianum

"

patulum henryiLycium species

Maackia amurensis

Marsdenia erecta

Rhododendron viscosum

Rhus glabraRosa setigeraRubus odoratus

Spiraea salicifoliaStewartia koreana

"

pseudo-camelliaTilia euchlora

((

petiolarisC("

tomentosa

Viburnum setigerum aurantiacum

Mid-July

Aesculus parvifloraAlbizzia julibrissin roseaAmorpha brachycarpa

(("

canescens

Ampelopsis aconitifolia((

cordata

Berberis aggregataCampsis radicansClematis jackmaniCyrilla racemifloraDiervilla lonicera

Hydrangea cinerea"

paniculata praecox((

quercifolia((

radiata" ."

serrata

Hypericum arnoldianum((

densiflorum((

frondosum

Koelreuteria paniculataLigustrum quihouiLonicera heckrotti

(( ,19

sempervirensRosa wichuraiana

Securinega sufl~ruticosaStewartia ovata

Symphoricarpos chenaulti

56

Symphoricarpos orbiculatusTamarix odessana

"

pentandraYucca filamentosa

Late July

Acanthopanax senticosusAbelia schumanni

Ampelopsis brevipedunculataAralia spinosaBuddleia albiflora

Calluna vulgaris and varieties

Cephalanthus occidentalisClethra acuminata

" alnifolia

" 6

barbinervis

Hypericum prolificumKalopanax pictusLespedeza bicolorNandina domestica

Oxydendrum arboreumSorbaria arborea

August

Abelia grandifloraAralia chinensis"

elata

Buddleia davidi varieties

Caryopteris incanaClematis virginianaClematis vitalba

Clerodendron trichotomum

Hibiscus syriacus varieties

Hydrangea macrophy-lla"

paniculata«

66 grandifloraHypericum dawsonianumLagerstroemia indicaLespedeza cyrtobotryaPolygonum auberti

’ Rhus copallinaSophora japonicaVitex agnus-castus«

negundo incisa

SeptemberBaccharis halimifolia

Clematis paniculataElsholtzia stauntoni

Franklinia alatamaha

October

Hamamelis virginianaLespedeza japonica

DONALD V~·YMAN