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 UNITED STATES 
 
 HOME AND 
 
 PREPARED BY 
 
 DEPARTMENT 
 
 GARDEN BULLETIN 
 
 AGRICULTURAL 
 
 OF AGRICULTURE 
 
 NUMBER 199 
 
 RESEARCH 
 SERVICE 
 
CONTENTS 
 
 Page 
 
 Types of lilacs 1 
 
 Planting lilacs 3 
 
 What to plant 3 
 
 When to plant 3 
 
 Where to plant 3 
 
 How to plant 3 
 
 Caring for lilacs 4 
 
 Propagating lilacs 4 
 
 Root Sprouts 4 
 
 Layering 4 
 
 Cuttings, Cleft and Bud Grafts 5 
 
 Pests 5 
 
 Photos of lilac species supplied by 
 Highland Park Herbarium, Rochester, 
 New York and Arnold Arboretum, 
 Jamaica Plain, Massachusetts. 
 
 Department publications contain 
 public information. They are not 
 copyrighted and can be reproduced 
 in whole or in part with or without 
 credit. 
 
 u 
 
Growing 
 
 LILACS 
 
 By Henry M. Cathey, ARS research horticulturist 1 
 
 Lilacs are versatile flowering shrubs, 
 which have a wide range of uses in the 
 home garden. They can serve as border 
 plants with smaller shrubs, as corner 
 plantings, as windscreens, or as flower- 
 ing hedges. Both plants and flowers are 
 very attractive. 
 
 Although lilacs display flowers that 
 are among the most delicate of the orna- 
 mentals, the plants are among the most 
 hardy. Some varieties can survive win- 
 ter temperatures of — 60° F. They are 
 therefore suited to all parts of the 
 United States except the South, where 
 winters are too mild to provide the 
 plants with the seasonal rest period they 
 need. 
 
 Lilac plants often grow and continue 
 to flower for many years even if totally 
 neglected. Normally, the only care they 
 need is pruning to keep them within 
 bounds. 
 
 The plants range from 3 feet to as 
 much as 30 feet in height, depending on 
 the age or type grown. Most, however, 
 remain under 10 feet. 
 
 Lilac flowers can be white, violet, 
 blue, true lilac, pink, magenta, purple, 
 or variations of these colors. Depending 
 on where you live, and the lilac vari- 
 eties you choose, lilacs can provide 
 color and fragrance from April through 
 June. 
 
 TYPES OF LILACS 
 
 There are many species and kinds of 
 lilacs. Extensive cross-breeding, how- 
 ever, has made these species very much 
 alike. Even botanical experts sometimes 
 find them difficult to identify. 
 
 All lilacs belong to the genus Syringa. 
 Common to most kinds are unlobed 
 leaves and flowers that grow in clusters. 
 Among the best known are the 
 following: 
 
 Common lilac (Syringa vulgaris), 
 as the name implies, is the best known 
 of all the lilacs in the United States. 
 This shrub can be as tall as 20 feet, and 
 the flowers are fragrant and usually 
 lilac-colored, although they can be of 
 other hues. Leaves are somewhat 
 heart-shaped and smooth. 
 
 Persian lilac [Syringa persica) can 
 grow to a height of 10 feet. The fra- 
 grant flowers are a pale lilac color and 
 are about half the size of those of the 
 common lilac. The leaves are narrow 
 on drooping branches. This plant 
 makes a good hedge. 
 
 Chinese or Rouen lilac (Syringa 
 chinensis) is a cross between the Per- 
 sian and the common lilac. It is some- 
 what taller than the Persian. The 
 fragrant, lilac-purple flowers are about 
 the same as common lilacs, but appear 
 
 1 Florist and Nursery Crops Laboratory, Beltsville Agricultural Research Center-West, USDA, Beltsville, Md. 20705 
 
The common lilac, Syringa vulgaris. 
 
 in greater profusion. The leaves are 
 smaller than those of the common lilac. 
 
 Late or Himalayan lilac {Syringa 
 villosa) blooms later than other lilacs. 
 It grows to a maximum of about 10 feet 
 and produces fragrant clusters of rose- 
 lilac blossoms. The leaves are pointed 
 and have hairy veins. 
 
 Hungarian lilac (Syringa josikaea) 
 resembles the late lilac in many ways, 
 but the fragrant flowers are darker, and 
 the leaf veins are smooth, not hairy. 
 
 Largeleaf lilac (Syringa oblata) is 
 among the very first lilacs to bloom in 
 the spring. It grows to a height of 
 about 12 feet, and has fragrant flowers. 
 Its relatively big, broad leaves are 
 tinged with red when young, and turn 
 red in autumn. 
 
 Littleleaf lilac (Syringa micro- 
 phylla) is a round, low, bush-like plant 
 that seldom grows more than 5 feet tall. 
 It produces small, late-blooming, fra- 
 
 grant, lilac flowers. Both leaves and 
 flowers of this species are small. 
 
 Dwarf Korean lilac (Syringa pale- 
 binina) is an even shorter bush than 
 the littleleaf lilac and seldom grows 
 more than 4 feet tall. Its lilac flowers 
 are fragrant. 
 
 Tree lilacs (Syringa amurensis) re- 
 semble small trees, and can reach a 
 height of 30 feet. In early summer, tree 
 lilacs produce spectacular clusters of 
 off-white, privet-like blooms. A com- 
 mon variety is the Japanese tree lilac 
 (Syringa amurensis japonica) , which 
 produces huge clusters of yellow-white 
 flowers late in the season. It grows 25 
 to 30 feet tall. 
 
 Other fairly well-known types of 
 lilacs are: Syringa pekinensis, an at- 
 tractive shrub with long, yellow-white, 
 nonfragrant flowers; Syringa reflexa, 
 the "nodding" lilac, so named because 
 its pink flowers hang somewhat limply 
 on the 10- to 12-foot bush; Syringa 
 prestoniae, a very hardy species that 
 results from crossing the nodding lilac 
 
 Nodding lilac, Syringa reflexa. 
 

 
 
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 Syringa prestoniae, hardy cross between the 
 nodding lilac and late lilac. 
 
 and the late lilac; and Syringa pubes- 
 cens, a 6- to 12-foot shrub with pale 
 flowers that are among the most fra- 
 grant of all varieties. 
 
 A new, free-flowering lilac, named 
 Cheyenne, will withstand the extra cold 
 temperatures and severe winters of the 
 northern States. Cheyenne grows to a 
 height and spread of about 8 feet, and 
 has dense, symmetrical growth. The 
 highly fragrant flowers are a distinctive 
 and delicate shade of light blue — dif- 
 ferent from most other lilacs. 
 
 When selecting lilacs, keep in mind 
 how you want to use them, and choose 
 varieties accordingly. Your nurseryman 
 can suggest the best types for your 
 particular needs. 
 
 PLANTING LILACS 
 
 What To Plant 
 
 Most commonly, you would buy 
 nursery-growTi plants for plantings 
 
 around the house and garden. They 
 should be 2- to 4-feet tall, big enough 
 to stand transplanting. You can also 
 buy larger plants that are balled and 
 burlapped. 
 
 When To Plant 
 
 The best time to plant lilacs is in the 
 fall after the leaves have dropped, but 
 before the ground freezes. You can 
 plant lilacs in the spring before the 
 buds start to unfold. Spring periods 
 are very short, however, and trans- 
 planting at this time is recommended 
 only in areas where winters are very 
 severe. Lilacs planted in the fall usually 
 have a better chance to survive, because 
 new roots get a head start in spring 
 before the shrub leafs out. 
 
 Where To Plant 
 
 Lilacs grow best in an open area that 
 offers good drainage. They need room, 
 and thrive where exposed to sun and 
 wind. A hillside or slope in full sun is 
 ideal. But they will grow in most garden 
 settings. 
 
 The ideal soil for growing lilacs is a 
 loam that is not too rich, and that is 
 neutral or slightly alkaline. Yet, lilacs 
 will grow well in all types of soil, ex- 
 cept for acid soil. If the soil is low in 
 fertility, mix in cow manure or a fer- 
 tilizer low in nitrogen and high in 
 phosphate and potash. Bonemeal is a 
 good fertilizer for lilacs, and it contains 
 the lime that can sweeten acid soil. 
 
 How To Plant 
 
 Dig a hole big enough to accommo- 
 date the roots without bending or 
 breaking them. Work a bucket of peat 
 moss and a cup of 5-10-5 fertilizer into 
 the hole. This will promote the develop- 
 ment of a good root system and hasten 
 
the establishment of the plant. Mix peat 
 moss and fertilizer with the soil 
 throughout the area. Good soil prep- 
 aration will aid in producing a good- 
 looking, heavily flowering plant. 
 
 Set the plant 2 or 3 inches deeper 
 than it grew in the nursery, and work 
 topsoil in around the roots. Setting the 
 plant deeper can kill it. Pour in water 
 and let it drain away. Then fill in the 
 hole to ground level with more topsoil. 
 
 Use a 3-to 4-inch mulch of leaves or 
 hay around the plant in the fall to keep 
 moisture in and to prevent heaving — 
 the alternate freezing and thawing of 
 soil. Heaving can kill the plant. After 
 the soil settles? the level around the 
 plant should be even with the sur- 
 rounding soil. Allow 6 feet or more 
 between most lilac plantings. 
 
 CARING FOR LILACS 
 
 Lilacs require a minimum of care. 
 They seldom need supplemental wa- 
 ter — only in conditions of drought. If 
 weeds grow around the plant, pull them 
 out by hand ; then apply mulch. Do not 
 cultivate around the base of the plant. 
 
 Do not overprune lilacs. Let the plant 
 develop several branches from the base, 
 instead of only one or two. This allows 
 you to remove stems that have grown 
 too tall, or have been attacked by dis- 
 eases or insects, and still have flowering 
 wood. 
 
 Pruning is unnecessary for the first 
 3 or 4 years. Thereafter, limit pruning 
 to the removal of weaker wood from 
 the center of the bush. This prevents a 
 thicket from developing. You should do 
 this soon after flowers have fallen. 
 
 Do not prune in late summer, fall, or 
 winter; late pruning often results in 
 removal of flower buds. 
 
 Old bushes with runaway growth will 
 
 need severe pruning. In such cases, re- 
 move about a third of the height of the 
 plant each year for 3 years, until the 
 old wood has been cut to about level. 
 (See illustrations on pages 6 and 7.) 
 
 Remove dead flowers soon after they 
 wither. This helps insure vigorous 
 growth for the rest of the season and 
 abundant blooming the following year. 
 
 PROPAGATING LILACS 
 
 Lilacs can be propagated from root 
 sprouts, by layering, by cuttings, and 
 by cleft and bud grafts. Each method 
 has its advantages and disadvantages 
 in time and degree of difficulty. The 
 easiest methods for the home gardener 
 are root sprouts and layering, using 
 a named variety. 
 
 Growing lilacs from seed is not rec- 
 ommended. Because most lilacs are hy- 
 brids, plants grown from seed will not 
 produce plants just like the parent 
 plant. Few seedlings are worthy of a 
 place in the home garden. 
 
 Root Sprouts 
 
 Root sprouts provide the simplest 
 and most usual way of propagating 
 the common lilac. Some lilacs send out 
 suckers near the base of the plant. Dig 
 up these new sprouts in the fall and 
 transplant them elsewhere in the garden 
 or in a nursery. They often develop 
 into satisfactory plants in about 3 
 years. This method, however, will not 
 be satisfactory for grafted plants, be- 
 cause the suckers will not be like the 
 tops of the plants. Look for a graft 
 union near the soil line to determine if 
 a plant is grafted. 
 
 Layering 
 
 Layering is an easy, but slow process 
 for increasing lilac plants in the home 
 
garden. The new plants are identical to 
 the parent, even if the parent plant was 
 grafted. It is a satisfactory method of 
 propagation for the home gardener 
 with limited equipment and time. 
 Layering is most successful in spring 
 or late summer, since cool weather is 
 an aid to rooting. 
 
 Start layering by working peat or 
 leafmold and sand into the soil where 
 the branch is to be layered. Next, make 
 a slanting 2-inch cut on the upper side 
 of the branch about a foot from the tip. 
 Dust rooting stimulant on the cut. Bend 
 the branch down, and fasten it to the 
 ground at a point between the trunk 
 and the wound. Use a wooden peg or 
 wire wicket, or simply weigh it down 
 securely with a stone. Bend the tip up- 
 right at the wound, and as you do, 
 twist the tip a half-turn to open it. Then 
 place another peg or pin over the 
 branch at the point of the wound, and 
 mound 3 or 4 inches of firmly packed 
 soil over the wound. Place straw or leaf 
 mulch on the mound, and water 
 frequently. 
 
 If you layer in the spring, the branch 
 should develop roots by the following 
 spring. If you layer in the fall, roots 
 will develop by the second spring. 
 When roots have developed, you can 
 cut the new plant free from the parent. 
 Leave the new plant in place for 3 weeks 
 to recover from the shock of being cut. 
 Then transplant it to a nursery bed and 
 tend it for a year or more. 
 
 To prevent water loss that can kill 
 the new rooted layers, prune one-third 
 of their original length from all side 
 branches of these rooted layers as soon 
 as you plant them in the nursery bed. 
 As a further measure to prevent water 
 loss, screen the new plants to shade 
 them from the sun. A makeshift screen 
 
 will do — burlap or other porous mate- 
 rial on a simple wood frame, for ex- 
 ample. You can remove the screen after 
 the first winter. By then, plants should 
 be strong enough to transplant from 
 the nursery to their permanent 
 locations. 
 
 Cuttings, Cleft And 
 Bud Grafts 
 
 Cuttings, cleft grafts, and bud grafts 
 are still other methods of propagating 
 lilacs. You can root lilac cuttings from 
 suckers at the base of an older plant 
 for use as understock. Cuttings from 
 terminal growth of new wood can be 
 grafted onto these. This method pro- 
 duces high-quality plants. The process 
 requires a great deal of knowledge, 
 however, and takes several months in 
 a greenhouse or glass-covered frame, 
 where the air can be kept moist con- 
 tinuously. Cleft grafting is the most 
 common way of propagating the named 
 varieties of lilacs on a commercial 
 basis. And bud grafting is an especially 
 economical and a very rapid method 
 if you want to grow many new plants. 
 
 The techniques for propagating by 
 cuttings and by cleft or bud grafting 
 are detailed in Home and Garden Bul- 
 letin No. 80, "Home Propagation of 
 Ornamental Trees and Shrubs". You 
 can obtain a copy from the Office of 
 Communication, U.S. Department of 
 Agriculture, Washington, D.C. 20250. 
 The information applies generally to 
 many woody plants, including lilacs. Be 
 sure to include your return address and 
 ZIP code number when ordering. 
 
 PESTS 
 
 A number of insects and diseases 
 attack lilacs, but only a few cause 
 serious injury. 
 
Pruning Lilacs 
 
 OLD OVERGROWN PLANT 
 
 Few flowers 
 Base heavily shaded 
 
 WRONG 
 
 Stems trimmed 
 all to same level 
 
 Dead stems 
 left in clump 
 
 Pruned when 
 in growth 
 
 Side 
 
 branches 
 
 and all 
 
 dead 
 
 wood 
 
 removed 
 
 All basal 
 iJL 'shoots 
 left on 
 plant 
 
 Too tall for area 
 
 Many small branches 
 
 Several dead branches 
 
 Crowded stems at base 
 
 RIGHT 
 
 Pruned 
 just after 
 flowering 
 Spring 
 
 Ml ]//3of tall 
 ^ranches 
 / pemoved 
 4a ch year 
 'for 3 years 
 
 // Branches 
 cut off at 
 soil line 
 
THREE-YEAR PLAN 
 
 Remove 1/3 Of Tall Branches Each Year For 3 Years 
 
 Old branches 
 (1/3 left) 
 
 Many new 
 branches 
 
 Stumps from 
 old branches 
 
 V Old 
 branches 
 (2/3 left) 
 
 1 YEAR LATER 
 
 All old branches gone; 
 Looks like a new, 
 young plant 
 
 Stumps completely 
 covered with new 
 growth 
 
 TbXjjP^-^ Stumps 
 
 2 YEARS LATER 
 
 Thinned and trimmed final time 
 
 Trimmed and trained 
 every year to control 
 height and to allow for 
 growth of strong, new 
 shoots 
 
 3 YEARS LATER 
 
Powdery mildew is the most common 
 disease. It appears on foliage in late 
 summer, and gives leaves a whitish, 
 dusty appearance. You can control it 
 by dusting with sulfur as soon as you 
 notice the disease. 
 
 Oystershell scale and San Jose scale 
 pierce the bark and suck sap from the 
 plant, thus weakening flower-bearing 
 stems. To control scale insects, use 
 either carbaryl or malathion. 
 
 Lilac borers, as the name suggests, 
 burrow into the wood of the plant, 
 sometimes leaving small amounts of 
 sawdust as evidence of their presence. 
 Larvae are creamy-white caterpillars 
 
 
 
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 Powdery mildew. 
 
 Oystershell scale. 
 
 about %-inch long. These larvae usu- 
 ally concentrate on old branches, but 
 they may also go after healthy new 
 wood. They are especially damaging to 
 grafted plants. A serious, uncontrolled 
 infestation can affect the entire bush, 
 causing leaves to wilt and stems to 
 break off. You may have to remove 
 seriously riddled branches. You can 
 dig borers from the stems with a knife, 
 or kill them by probing their burrows 
 with a wire. 
 
 Borers can be controlled with endo- 
 sulfan spray. Apply spray to the main 
 trunk and branches in early May and 
 repeat 2 or 3 times at 3-week intervals. 
 For further information on pests of 
 lilacs, contact your county Agricultural 
 Extension Service. 
 
USE OF PESTICIDES 
 
 This publication is intended for nationwide distribution. Pesticides are 
 registered by the Environmental Protection Agency (EPA) for countrywide 
 use unless otherwise indicated on the label. 
 
 The use of pesticides is governed by the provisions of the Federal Insec- 
 ticide, Fungicide, and Rodenticide Act, as amended. This act is administered 
 by EPA. According to the provisions of the act, "It shall be unlawful for 
 any person to use any registered pesticide in a manner inconsistent with 
 its labeling." (Section 12(a) (2) (G).) 
 
 EPA has interpreted this Section of the Act to require that the intended 
 use of the pesticide must be on the label of the pesticide being used or 
 covered by a Pesticide Enforcement Policy Statement (PEPS) issued by 
 EPA. 
 
 The optimum use of pesticides, both as to rate and frequency, may vary 
 in different sections of the country. Users of this publication may also wish 
 to consult their Cooperative Extension Service, State Agricultural Experi- 
 ment Stations, or County Extension Agents for information applicable to 
 their localities. 
 
 The pesticides mentioned in this publication are available in several dif- 
 ferent formulations that contain varying amounts of active ingredient. Be- 
 cause of this difference, the rates given in this publictaion refer to the 
 amount of active ingredient, unless otherwise indicated. Users are reminded 
 to convert the rate in the publication to the strength of the pesticide 
 actually being used. For example, 1 pound of active ingredient equals 2 
 pounds of a 50 percent formulation. 
 
 The user is cautioned to read and follow all directions and precautions 
 given on the label of the pesticide formulation being used. 
 
 Federal and State regulations require registration numbers. Use only 
 pesticides that carry one of these registration numbers. 
 
 USDA publications that contain suggestions for the use of pesticides are 
 normally revised at 2-year intervals. If your copy is more than 2 years old, 
 contact your Cooperative Extension Service to determine the latest pesti- 
 cide recommendations. 
 
 The pesticides mentioned in this publication were federally registered 
 for the use indicated as of the issue of this publication. The user is cau- 
 tioned to determine the directions on the label or labeling prior to use of 
 the pesticide. 
 
UNIVERSITY OF FLORIDA 
 
 3 1262 08582 9231 
 
 l/de 'Pufaiakd £0^1/ 
 
 FOLLOW THE LABEL 
 
 U.S. pinlKEKT OF AGIICUITUIE 
 
 Washington, D.C. 
 
 Issued August 1973 
 Slightly revised October 1977 
 
 romtt-b j t he n n pn r in t rn rl r nt n f r onrni ' iitf i " - e - ■'ir.vnrnmpnt Printi ng-affioo 
 
 ■it U.S. GOVERNMENT PRINTING OFFICE : 1977— O-244-l 12