GROUP III – Difficult at times
This Page Last Updated: October 21, 2009
Special Condition Key:

A prefers more acidic soil; try 1 Tablespoon white vinegar in 1 gal. water monthly
B brown leaf tips indicate salt burn/salt build-up, often from too much or too little watering
C subject to iron or manganese chlorosis (best iron source is a chelated mineral)
D subject to random branch die-back (which may be due to wrong-timed pruning)
F frost-sensitive, so protect with frost cloth or bring indoors if a hard freeze is expected
I more adaptable for use as an indoor bonsai than other plants, but still requires a certain level of temperature, light and humidity in order to be healthy and to thrive
L may drop some leaves when relocated or repotted
M very attractive to spider mites, so hose-spray and keep in very good air-flow
P pinch first set of leaves when opened, the next will be smaller in size
R do not root prune if at all possible; never bare root this kind of plant
S leaves sunburn/windburn easily, so provide shelter/protection
U larger specimens can take full sun most of day here when established
W bark is tender or branches are brittle, so wire carefully, if at all, to avoid scars and damage
X Outside of a container, this is considered an invasive plant in some areas: err on the side of caution and discard this plant’s clippings or a “dead” specimen in a trash bag, not just on the ground.
^ evergreen
% deciduous/semi-deciduous
* can bloom as bonsai

Note: Plants labeled as susceptible to chlorosis when grown in the ground should not have this problem in a container with a quality soil mix and regular fertilizer schedule. “Established” plants are firmly rooted and producing a good growth of new buds which have opened up into leaves.



Japanese Boxwood (Buxus microphylla japonica) F ^*


        prefers alkaline soil; be careful not to damage the shallow roots; needs a little winter chill; best bark texture can be found on 5 gallon+ size specimens; best time to trim is right before monsoon season starts in June or July; dig a hedge/landscape specimen when it is dormant and collect with as large of a rootball as possible, put in an oversized pot and let it recover for a year, doing light amount of trimming and thinning only; “Kingsville” is smallest-leaved variety available.    [Buxaceae; Euphorbiales]     SEE ALSO BCI Plant Sheet.


Camellia (Camellia sp.)   A,C,F,R,S,W ^*


       some say needs a little winter chill (in 50’s° F at night) for adequate flowering although is very frost-sensitive; prefers partial shade; do not fertilize when in bloom; feed every two to three weeks during growing season; hard prune during winter after flowering, then remove any spent flowers and trim to desired shape, though some say not easily shaped; CAN NOT be allowed to dry completely; increase watering during active growth, and when plant is in bloom; some growers recommend using Reverse Osmosis (R.O.) water; very prone to scale, aphid bugs, red spider mites, sooty mold, and weevils; should be repotted every two to three years, always in early spring months, but make sure you use lime-free humus rich soil, as it does not tolerate lime well; Sasanqua varieties have the smallest blossoms.    [Theaceae; Ericales]     SEE ALSO BCI Plant Sheet.


Wintersweet (Chimonanthus praecox) W %*


        buds back well on old wood, so “Clip & Grow” rather than wire; give afternoon shade.   [Calycanthaceae; Laurales]


Arizona Cypress (Cupressus arizonica glabra) U ^


         [Cupressaceae; Pinales]


Gardenia (Gardenia augusta) M ^*


        likes full sun; use blood meal as fertilizer; use fast-draining soil mix with lots of organic matter; keep crown of roots uncovered; subject to scale and spider mites; same plant as G. jasminoides ; “Radicans” is smallest-leaved variety available.   [Rubiaceae; Gentianales]     SEE ALSO BCI Plant Sheet.


Lavender Starflower (Grewia occidentalis) A,C,I,U %*


        a fast grower; prefers lots of water; takes heavy top pruning; leaves wilted from temporary nonlethal water deprivation will not rehydrate, but will eventually turn black and be shed as the plant puts out new ones.    [Tiliaceae; Malvales]


Jacaranda (Jacaranda mimosifolia) F %


        keep soil uniformly moist throughout the year; yellow leaves dropping could be due to too much water; shrinking brown leaves could be due to dry root ball; can be vigorously root pruned and transplanted in the spring; shorten new shoots to one or two pairs of leaves after they have produced at least four or five pairs; regularly remove all large leaves.     [Bignoniaceae; Lamiales]


Creosote / Greasewood (Larrea tridentata) M,R,U ^*


        pinch buds, don’t cut them; this plant is difficult to establish, but then hardy; roots grow slowly; it actually likes and does well with more water than you’d expect; trimming in the autumn may encourage spring blossoms; needs to be wired once or twice a year to keep the small branches horizontal, best in autumn, then remove in late October or November; wild-dug specimens can be large-trunked but very iffy in surviving: try to get as much of rootball as possible, plant in large/over-size container, and give it time; recommended digging is right after a rain anytime of year.    [Zygophyllaceae; Zygophyllales]


Liquidambar / Sweet Gum (Liquidambar sp.) C,S %


        can be used instead of Japanese Maple; prefers a neutral or slightly acid soil mix; remove all large terminal buds from the branches in the spring to encourage side buds; repot less often; can throw occasional large/disproportioned leaves; give as much sun as possible to set up good autumn coloring; you don’t have to leaf prune this plant.    [Hamamelidaceae; Saxifragales]     SEE ALSO BCI Plant Sheet.


Magnolia (Magnolia sp.)   %*


        leaves are disproportionately large, but the flowers make this tree a worth-while bonsai; prune after flowers start to wither; cut the top off the plant and a number of buds will sprout below; branch placement not always good; M. stellata said to be best for bonsai.    [Magnoliaceae; Magnoliales]


Crab Apple (Malus sp.)   %*


        fertilize once in the spring; if you fertilize during the summer it could dehydrate the plant; might show a little windburn on the leaves; needs a winter chill to do well and develop flower buds; the flowers develop out of last year’s growth; needs full-day filtered sun; water only when showing wilt: watering every day unnecessarily can quickly kill the plant due to root rot; prefers being in a deeper pot for cool roots; needs a period of freezing weather to stay healthy and look its best; keep soil away from direct contact with the bark of the trunk; can be a very fast grower; keep upwind from junipers or keep as far away as possible from junipers — bonsai or landscape specimens — because junipers can spread rust infection to crab apples.    [Rosaceae; Rosales]    SEE ALSO BCI Plant Sheet.


Eldarica or Goldwater Pine  (Pinus eldarica) R ^


       see other pines.     [Pinaceae; Pinales]


Italian Stone Pine (Pinus pinea) B,M,R ^


       see other pines; yellow needle tips means soil too wet, but don’t let roots dry out; best bargains can be found right after Christmas, especially in the garden section of department stores (just be sure your choice was watered regularly).    [Pinaceae; Pinales]


Pear, Flowering (Pyrus calleryana) C,U %*


      recommend using Reverse Osmosis (R.O.) water; sometimes has fungus problems on its roots; showy flowers for only about a month in January; leaves come out and harden in February/March; best pruning time is May but not after August when flower buds start to develop; filtered sun best; full sun O.K. October to April.   [Rosaceae; Rosales]


Oak (Quercus sp.)  %


        NEVER leaf prune or defoliate oaks; prefer deeper pots because they root deeply; leaf burn on edges indicates hard water salts, so use Reverse Osmosis (R.O.) water; can be bare-rooted when dormant; some oaks have dark brown roots, which are healthy but not the expected light color; cut tap root only if tree already has a good-sized ball of fine feeder roots.     [Fagaceae; Fagales]


Rosemary (Rosmarinus officinalis M,R,U ^*


         do not let go dry; a fast grower: keep pruned; repot in January or February; pale green leaves are dying/dead and will never regrow, plus that particular stem is dead also; in Phoenix seems to have a short lifespan of only a couple of years when potted.    [Lamiaceae; Lamiales]


Chinese Sweet Plum (Sageretia theezens) D,F %*


        fast grower; likes water; will not tolerate cold drafts or a constantly dry atmosphere — mist with Reverse Osmosis (R.O.) water, especially if in a heated indoor location; wiring not often used with; needs some shade; may take a few years to hold on to branches rather than drop them; said to do better in a peat-based soil as opposed to the typical bonsai soil; needs frequent, at least annual, repotting in fresh soil; this is a hungry species and seems to need high fertility and lots of root space to grow vigorously; the type of fertilizer makes a difference: responds best to ammoniacal forms of nitrogen; though can put on a lot of shoots and foliage quickly, it forms a larger trunk at a painfully slow rate; seems to put on a rapid growth spurt after the heat of summer and the onset of cooler weather and shorter days.    [Rhamnaceae; Rosales]     SEE ALSO BCI Plant Sheet.


Chinese Tallow Tree (Sapium sebiferum) A,D % X


         get during autumn so you can check leaf color; no high Nitrogen fertilizer in autumn; tree exudes an allelopathic chemical which prevents growth of other types of plants, so don’t use in multi-culture forests.    [Euphorbiaceae; Euphorbiales]


Australian Bush Cherry  (Syzygium paniculatum) B,D,F,I ^


        accepts low light levels, but does better when brighter; prune lightly regularly; let soil dry slightly before watering; it is the same plant as Eugenia paniculatum.     [Myrtaceae; Myrtales]     SEE ALSO BCI Plant Sheet.


Cape Honeysuckle (Tecomaria capensis) D,F,U ^*


        trunk very slow — seemingly slower than most other types we use — to fatten in pot, so best to start with as large a specimen as possible; fast growth spurts; needs to be cut back strongly once or twice a year to hold shape, some dieback might follow.    [Bignoniaceae; Lamiales]