Flowering shrub profiles: butterfly bush, lilac, hydrangea, hibiscus and companions.
Compare the botanical identities, source-listed light and soil conditions, container evidence and local-calendar inputs for butterfly bush, crepe myrtle, dwarf lilac shrub, lilac tree, forsythia shrub, hibiscus shrub, hydrangea.
Choose the plant before choosing the quantity
Flowering shrubs vary in botanical identity, growth habit, seasonal interest and regional spread concerns. The source entries below are named examples or genus summaries; none sets a universal pruning rule, screening guarantee or structural support specification.
The entries report the cited taxon’s growing conditions and descriptive dimensions. A mature width is separate from planting spacing; multiple light, moisture or life-cycle categories can reflect a genus, cultivar range or climate differences. Use the exact nursery label and local guidance to choose inputs. Soil categories describe the source record and supply no amendment recipe.
Butterfly bush
Butterfly bush: the cited botanical record is Buddleja davidii. Check local invasive status and the exact cultivar before considering this plant; do not infer that a named cultivar removes every regional restriction.
Source-listed light conditions: full sun. Drainage and moisture descriptions: good drainage, occasionally dry, occasionally wet. Soil categories: clay, high organic matter, loam (silt), sand, shallow rocky. Listed soil pH categories: Neutral (6.0-8.0).
Reference dimensions: height: 6 ft 0 in to 12 ft 0 in; width: 4 ft 0 in to 15 ft 0 in. Life cycle listed: perennial, woody. Flowering season in the reference region: fall, summer. The source’s location field does not establish container use; request a cultivar-specific container record.
Crepe myrtle
Crepe myrtle: the cited botanical record is Lagerstroemia indica. The species example does not fix the size of dwarf, hybrid or tree-form cultivars.
Source-listed light conditions: full sun. Drainage and moisture descriptions: good drainage, moist, occasionally dry, occasionally wet. Soil categories: clay, high organic matter, loam (silt), sand, shallow rocky. Listed soil pH categories: Acid (<6.0); Alkaline (>8.0); Neutral (6.0-8.0).
Reference dimensions: height: 6 ft 0 in to 30 ft 0 in; width: 6 ft 0 in to 30 ft 0 in. Life cycle listed: woody. Flowering season in the reference region: summer. Container use is explicitly listed in the source.
Source: NC State Extension Plant Toolbox: Lagerstroemia indica
Dwarf lilac shrub / Lilac tree
Dwarf lilac shrub / Lilac tree: the cited botanical record is Syringa vulgaris. Shrub, compact and tree-form lilacs are distinct selections; use the complete species and cultivar label.
Source-listed light conditions: full sun, partial shade. Drainage and moisture descriptions: good drainage, moist. Soil categories: clay, high organic matter, loam (silt). Listed soil pH categories: Alkaline (>8.0); Neutral (6.0-8.0).
Reference dimensions: height: 8 ft 0 in to 16 ft 0 in; width: 6 ft 0 in to 12 ft 0 in. Life cycle listed: perennial. Flowering season in the reference region: spring. The source’s location field does not establish container use; request a cultivar-specific container record.
Forsythia shrub
Forsythia shrub: the cited botanical record is Forsythia. Species and compact selections differ in size; use the selected cultivar record.
Source-listed light conditions: full sun, partial shade. Drainage and moisture descriptions: good drainage. Soil categories: clay, high organic matter, loam (silt).
Reference dimensions: height: 3 ft 0 in to 10 ft 0 in; width: 4 ft 0 in to 7 ft 0 in. Life cycle listed: perennial, woody. Flowering season in the reference region: spring. The source’s location field does not establish container use; request a cultivar-specific container record.
Hibiscus shrub
Hibiscus shrub: the cited botanical record is Hibiscus rosa-sinensis. Tropical and hardy hibiscus differ markedly; identify the species before deciding seasonal exposure.
Source-listed light conditions: full sun, partial shade. Drainage and moisture descriptions: good drainage, moist. Soil categories: high organic matter.
Reference dimensions: height: 4 ft 0 in to 10 ft 0 in; width: 5 ft 0 in to 8 ft 0 in. Life cycle listed: woody. Flowering season in the reference region: fall, spring, summer. Container use is explicitly listed in the source.
Source: NC State Extension Plant Toolbox: Hibiscus rosa-sinensis
Hydrangea
Hydrangea: the cited botanical record is Hydrangea. Species, flowering habit and final size differ; do not substitute a universal pruning or soil-treatment rule.
Source-listed light conditions: full sun, partial shade. Drainage and moisture descriptions: occasionally wet. Soil categories: clay, loam (silt), sand. Listed soil pH categories: Acid (<6.0); Alkaline (>8.0); Neutral (6.0-8.0).
Obtain mature dimensions for the selected nursery plant; the reference supplies no single size range. Life cycle listed: woody. Flowering season in the reference region: fall, spring, summer. The source’s location field does not establish container use; request a cultivar-specific container record.
Ninebark shrub
Ninebark shrub: the cited botanical record is Physocarpus opulifolius. Cultivar size and foliage differ; confirm the selection before allocating space.
Source-listed light conditions: full sun, partial shade. Drainage and moisture descriptions: good drainage, moist, occasionally dry. Soil categories: clay, loam (silt), sand. Listed soil pH categories: Acid (<6.0); Alkaline (>8.0); Neutral (6.0-8.0).
Reference dimensions: height: 5 ft 0 in to 8 ft 0 in; width: 4 ft 0 in to 6 ft 0 in. Life cycle listed: perennial. Flowering season in the reference region: spring, summer. The source’s location field does not establish container use; request a cultivar-specific container record.
Source: NC State Extension Plant Toolbox: Physocarpus opulifolius
Spirea shrub
Spirea shrub: the cited botanical record is Spiraea. Spiraea species differ in size, flowering timing and spread concerns; identify the selection.
Source-listed light conditions: full sun. Drainage and moisture descriptions: good drainage, moist, occasionally dry. Soil categories: high organic matter.
Obtain mature dimensions for the selected nursery plant; the reference supplies no single size range. Life cycle listed: woody. Flowering season in the reference region: spring. The source’s location field does not establish container use; request a cultivar-specific container record.
Viburnum
Viburnum: the cited botanical record is Viburnum. Species differ in size, light and seasonal habit; a genus record does not set a hedge specification.
Source-listed light conditions: full sun, partial shade. Drainage and moisture descriptions: good drainage, moist. Soil categories: clay, loam (silt), sand.
Reference dimensions: height: 4 ft 0 in to 20 ft 0 in; width: 2 ft 0 in to 18 ft 0 in. Flowering season in the reference region: spring. The source’s location field does not establish container use; request a cultivar-specific container record.
Weigela shrub
Weigela shrub: the cited botanical record is Weigela florida. Compact and larger selections need individual size records.
Source-listed light conditions: dappled sunlight, full sun, partial shade. Drainage and moisture descriptions: good drainage, moist. Soil categories: clay, loam (silt), sand. Listed soil pH categories: Acid (<6.0); Alkaline (>8.0); Neutral (6.0-8.0).
Reference dimensions: height: 6 ft 0 in to 10 ft 0 in; width: 9 ft 0 in to 12 ft 0 in. Life cycle listed: woody. Flowering season in the reference region: spring, summer. Container use is explicitly listed in the source.
Check the container and watering record
Where container use is listed, confirm the exact cultivar’s intended pot, drainage and medium with the nursery. A garden plant’s descriptive width does not determine a pot diameter or root-volume requirement. For dwarf trees, keep the named rootstock or compact cultivar dimensions with that record.
Observe the medium and follow the selected plant’s care instructions. A source describing moist soil does not supply a weekly irrigation volume. Pot size, plant size, medium and exposure belong in the watering record. Calculate litres only after the selected pot’s remaining fill has been measured.
Build a local planting calendar
Record your location, the selected cultivar and whether the purchase is seed, dormant stock or an actively growing plant. Obtain the local sowing or transplanting window for that material from the regional extension service or nursery. Record that window separately from the flowering season shown in the reference. Frost exposure, soil workability and the crop form can make a month from another region unsuitable.
For mixed orders, keep separate rows for each selection, its planned date, supplied along-row and across-row spacing and replacements. A species-wide width or a hardiness-zone label is insufficient to choose all of those values. This plan uses nursery or local guidance and contains no pesticide or nutrient treatment.
Turn the selected plan into a plant and bag order
For an independent illustrative 2 m by 1 m bed, supplied margins of 0.25 m on all sides and supplied spacings of 0.5 m in each direction produce four positions by two positions: eight plants. These are arithmetic inputs, not recommended spacings for the plants above. If the approved selection is sold in four-plant packs, the order is two packs.
For a separate container order with three measured empty-fill requirements of 8 L each, the total is 24 L. One selected 40 L bag covers the stated volume before any separately supplied allowance. The Soil Calculator calculates litres; it does not choose the growing medium, the container or a load-bearing location.
Use the matching calculator
Use this decision sequence
- Identify the exact species, crop type and cultivar or rootstock.
- Check the relevant source and local nursery guidance for growing conditions and planting window.
- Record supplied plant spacings or the selected container’s measured fill.
- Calculate positions and whole purchase packs separately for each selection.
Keep the quantities distinct
| Quantity or assumption | How to use it |
|---|---|
| Botanical record | A named example or genus record, not identification of an unknown plant. |
| Mature width | Descriptive size, separate from the selected planting spacing. |
| Planting date | A local window for the actual seed, dormant stock or transplant. |
| Watering | A plant and medium care decision, not the bed’s geometric volume. |
Worked comparison
A supplied four-by-two position plan contains eight plants and needs two four-plant packs. A separate three-pot order with 8 L of measured empty fill per pot needs 24 L of the selected medium, covered by one 40 L bag before any separately selected allowance.
Check before using the estimate
Check the exact cultivar and local restrictions before ordering. No species-wide figure establishes container fit, edible identity, support strength or planting success.
All dimensions, product properties, prices and specifications in this example are illustrative arithmetic inputs. Use the values from your measured plan, selected product data sheet and supplier quote. This guide does not choose construction specifications or certify safety.
Sources and product references
- NC State Extension: Buddleja davidii
- NC State Extension: Lagerstroemia indica
- NC State Extension: Syringa vulgaris
- NC State Extension: Forsythia
- NC State Extension: Hibiscus rosa-sinensis
- NC State Extension: Hydrangea
- NC State Extension: Physocarpus opulifolius
- NC State Extension: Spiraea
- NC State Extension: Viburnum
- NC State Extension: Weigela florida
References support the factual distinctions and scope described above. Growing guidance is regional and care instructions are product-specific. Worked numerical examples are independent illustrative arithmetic.
Calculation and scope checked 2026-10-13. Methods and scope.
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