Pruning Redbud Tree

We just bought a house that has a 10' redbud tree. The tree wasn't properly shaped when it was new so it has a lot of low branches, making it look almost like a bush. When and how much can be pruned. I know you said it shouldn't be pruned too much, but because of the way it looks we're tempted to get rid of it if it can't be helped. You have a great website, I looked at a lot of others for help and your's is the best.

Eastern Redbud (Cercis canadensis)

Thank you very much for rating my web-site so highly. I have often wondered if anyone has ever used the information in my articles to their benefit. This was my hope and reason for starting the web-site.

As for pruning your redbud tree, the proper time is either immediately after it has completed blooming or when the tree is dormant in later winter (before it starts to flower or leaf out).

It is best to prune and shape this tree while it is young because of its susceptibility to so many diseases (Canker, Verticillium Wilt, and Rebud Leaf Spot, for examples). When the tree is young, the limbs or branches are small, so the wounds that are made from pruning are naturally small and will heal over quickly. In contrast, pruning off large branches results in leaving large wounds which may take several years to heal over. The longer a wound takes to heal over, the greater the risk of a pathogen entering the wound and infecting the tree with a disease.

However, now that your tree is beyond the young stage, you will need to remove some large branches to acquire the desired results you are after. At no time should more than 25% of a tree's top growth be removed intentionally (a windstorm that may cause a lot of damage is unavoidable, for example). A tree needs branches and leaves to produce food through the process of photosynthesis. If too many are removed at one time, the tree can suffer from a shortage of food production and the 'dwarfing' effect may occur - the tree will remain the same size for many years, or even die. Secondly, if two many branches are removed at one time, the tree now has a lot of established roots, but fewer branches and leaves to use the moisture and nutrients the roots can supply it. So, the tree can put out a horribly huge amount of water sprouts or suckers from dormant, latent buds, which rob nutrients from the good parts of the tree besides ruining the entire shape and look of the tree, if they are not removed. A portion of the topgrowth should be removed each year until the desired effect is achieved.

So basically, remove a few of the larger lower branches (do not leave any stubs as these will not heal over) and any branches that cross or rub each other, up to a maximum of 25% of the trees topgrowth in the first season. Remove smaller branches where they join a larger branch, again leaving no stubs. Before any pruning is done, take a look at the tree and keep in mind the natural shape of the tree. One can not put a branch back on the tree after it is cut off. The idea is to form a tree with strong (branches are at right angles to the trunk), well spaced main branches that hold true to the shape of that species of tree, along with an open, airy canopy by removing crowded branches in the canopy. Tree wounds do not need to be painted with a tree dressing, but if you feel it is necessary, use only Pine Tar Tree Wound Dressing.

I hope your tree does well and will not have to be removed. Best of luck with the pruning!

When to Take Cuttings from Gardenia

When is the best time to try to establish a new cutting from a Gardenia Bush and how?

Gardenia jasminoides

Greenwood and semi-ripe cuttings root well at anytime of the year (March being the best time ). Both types of cuttings are taken from the current years growth. Basically, this means choosing shoots that have not become to woody (hard), nor those that are still soft and sappy. Use only healthy, disease free shoots. These cuttings differ from hardwood cuttings in that hardwood cuttings are mature wood and the stems or shoots do not have leaves when they are taken. Gardenias can also be air-layered to propagate new plants (see article on air-layering).

Make the cuttings about 3 inches long using the stem-tips. Cut the bottom of the cutting just below a node (joint) with a very sharp knife. Remove the bottom leaves from the cutting. Dip the bottom end of the cutting in a rooting hormone powder (shake off the excess powder) or gel, and insert immediately into the rooting medium so as not to let the cuttings wilt. Use vermiculite, a sand and peat mixture, or a commercially prepared rooting medium to root the cuttings. Water the cuttings in well and keep the media moist thereafter - never soggy wet. Place each cutting in its own little pot or tray, as gardenia's resent having their roots disturbed. Once they have rooted, they can be transplanted into proper soil by taking them out of the little pot, media and all, so as not to disturb the roots.

These cuttings generally root in 6 - 8 weeks, provided the air is kept humid around them, and they are given bottom heat (media) of 68 - 77 degrees F. (Cuttings have usually rooted when new growth is noticed at the tips, or when they resist a very gentle tugging). To keep them close (humid) and the media warm, they can be placed in a clear plastic bag and the container set on top of a refrigerator, for example.

Sanitation is a very important factor when trying to root cuttings. To start with, hands should be clean, tools should be sterile (dip them in a water and bleach solution), the rooting media must be sterile (vermiculite for example), and the containers should be new, or at least clean and sterile. The plastic bag should be removed from the cuttings for a short while at least every two days or so, to replace stale air with fresh air. Any decaying or moldy leaves should be removed immediately to prevent the spread of disease (Gray Mold) to other cuttings. If mold becomes a problem, treat the cuttings with a dusting of sulphur or other fungicide, and give the cuttings more ventilation (poking a few holes in the plastic bag, for example).

Over all, the secret to success is in providing the cuttings with good media aeration, a warm, humid environment and a warm rooting medium. Cuttings do not always strike (take root), but this is no reason to give up. In time, and with practice, one learns when to take the cuttings and when the wood is at the proper ripeness for easy rooting. Its like anything else, practice makes perfect. Best of luck!

Potted Plant Drainage

I have a peace lily that I got when my mother past away so it really means alot to me. I transplanted it from its original pot to a pretty pot, about a 3 gal. container. It does not have drain holes in it though. It did good for awhile then recently not so good. It is always wet but I think it is too wet. Should it have drain holes? I put some osmacote plant fertilizer in it and some natures helper on the top for some fresh soil. Need help please!!!

Peace Lily Spathiphyllum spp.

All plants should be given containers with drainage holes, otherwise, it is very difficult to thoroughly water the plant without over-watering it. Although peace lilies (Spathiphyllum sp.) should be kept moist at all times, the leaves will wilt if the soil is too moist, especially if temperatures are too cold. This is likely the problem with your plant. Night temperatures should not drop lower than 65 degrees F. The leaves will also wilt if the soil is too dry, but they will spring back quickly when watered again.

The peace lily needs low to medium light. At no time should it be placed in direct sunlight, they prefer shade. Flowers are produced in 200 - 300 footcandles of light.

Feed the plant every 3 months or so using a weak solution of houseplant fertilizer, only if it is growing well. Never fertilize an unhealthy houseplant.

The solution to the problem is to remove the plant from its container and repot it in a container which has drainage holes. Give it fresh potting soil which is composed of 2 parts peat moss, 1 part potting soil and 1 part perlite. Keep this mix moist at all times. Remove any rotted roots before repotting the plant. The plant can be divided at this time (at anytime of the year) to propagate new plants. I hope your plant recovers.

Where to Plant Evergreens

My husband and I purchased two globe cedars in June of this year. We planted them on the west side of our house. I would like some clarification on when and how to prepare them for winter. We have had a very dry summer here. To prepare them for winter, I was watering them approx once every two weeks since purchase. I have watered them once thoroughly in mid September and then once a week starting in October. I have made shrub covers but have not yet covered the cedars. Could you give me any additional ideas on how much more I should be watering and when I should cover them. The temperature has been going below 0 degrees Celcius some nights but during the day we are getting temperatures anywhere from 0 to high teen figures. Thank you for any additional input.

As a rule, cedars should be located on the north or east side of buildings or other objects such as trees, where they are not directly exposed to the winter sun. Evergreens transpire moisture all the year round, so placing them where the sun can thaw out the leaves during warm spells in winter and early spring only accelerates desiccation (drying out) of the leaves. Because the ground is frozen in winter and early spring, the roots are unable to replace the moisture lost by the leaves, and the leaves turn brown. It depends on how badly the leaves have been desiccated as to whether the plant will bounce back during the growing season, or whether the plant will die. In other cases, only a portion of the leaves will be lost. Browning of the leaves is also accelerated if the trees are growing in an unsheltered area where they are to the cold prevailing winds.

To help evergreens such as cedars make it through the winter, the ground should be soaked with water until the soil reaches 'field capacity'. This means water should be applied to the soil until the soil is no longer able to absorb anymore water. Field capacity has been reached when the water remains on the surface of the soil for quite some time before finally soaking away. This final watering of the evergreen should be administered approximately two weeks before the ground remains frozen, which in zone 2 for example, is the 2nd or 3rd week of October.

Because cedars are shallow rooted plants, it is important to protect their roots from hard frosts which heave and crack the ground, thus exposing their roots to the killing frost. A 6 inch layer of organic material such as leaves, straw or peat moss applied to the soil around the plant will help alleviate this problem. At the same time, the layer of mulch will keep the soil at an even temperature and prevent it from drying out. If peat moss is used as a mulching material, a little dirt sprinkled over it and then lightly watered to form a crust over the pile will prevent the moss from blowing away.

To protect young evergreens from the winter sun and the desiccation of drying winter winds, tie burlap to stakes which have been pounded into the ground around the tree. The burlap should not touch the tree. In early spring, when warm spells occur, but before the ground thaws, it is wise to spray the leaves with water ocassionally to help counteract high evaporation.

Trimming Ponytail Plant Roots

I have a ponytail palm that is over 5 ft tall. I made the BAD mistake of putting it into a 17 in. square pot. The bulb is quite large and roots are coming to the top. I want to transplant it, but a round pot has to be huge to handle a 17 X 17 sq. I need to trim back some of the roots to make it round again. 26 inch pots are the largest I have found around here. Is it ok to trim the roots? Thank you!

Ponytail Palm

Yes, it is OK to prune the roots, in fact, root pruning should be a routine chore whenever a plant requires repotting. Root pruning is as important to a house plant as is pruning the limbs or branches when they require pruning. Proper root pruning enables one to repot the plant in the same size container for many years, thus avoiding the need for huge containers and eventually a shortage of room for them. In the art of bonsai, root pruning is a regular practice. The roots are not merely pruned to keep the plant small in size, but to keep it healthy and actively growing in the same size container for many, many years.

How Roots Function

If we understand how roots function, then it is easier to understand why we can and should periodically root prune a potted plant. Think of a single root as having two parts, and each one of those parts having a special function, in so far as carrying water and nutrients to the plant above the soil. One part is the tiny, fine, white feeder roots at the very end of each root. These tiny feeder roots are the only part of the root that actually absorb moisture and nutrients (their special function). The other part of the root is the long, thick, woody part. The function of this part of the root is to transport the water and nutrients (absorbed by the tiny feeder roots) to the plant above the soil.

In nature, out of doors, a plants roots grow and travel long distances in search of moisture and nutrients. Over time, a potted plants roots also grow very long, but it is not necessary for them to do so, because the grower supplies the needed water and nutrients directly to them. In a container, roots grow to the sides of the container, and then down to the drainage holes at the bottom of the container (ending up as a tangled mass of roots) where there is a greater supply of air near the drainage holes, but very few nutrients. As the roots grow longer and longer, the tiny feeder roots at the end of each root become further and further away from the plant. The water and nutrients absorbed by these tiny roots now has to traved great distances to reach the plant. So, in reality, the long, thick, woody part of the root becomes inefficient and merely takes up space in the container.

So, the goal of root pruning is to shorten the distance water and nutrients have to travel through the root system to the plant. The solution is to prune the roots and regenerate a fibrous, compact, untangled root system. Wherever one of the thick, woody roots is pruned (cut off), new feeder roots will grow from behind the cut and branch out in all directions, forming a dense, compact system of small feeder roots close to the plant.

How to Root Prune a Rootbound plant

When a plant is root pruned, the rootball should be disturbed as little as possible, so it is best to do the job when the soil is moist (not dry or soggy), as moist soil is less likely to fall apart. The first step is to remove the rootball from the container. If there is a mass of roots circling the bottom of the rootball, these roots can be sliced off with a sharp knife or scissors rather than trying to untangle each root. Slice them off where the root mass meets the soil, gently prying the mass of roots back as you cut so you can see where you are cutting.

The next step is to remove any other large roots you notice at the bottom of the rootball (above the sliced off portion) or at the sides of the rootball. These large roots should be traced back into the rootball and cut off where they branch off, or where smaller roots exist. For every large root that is cut back, it will eventually be replaced by smaller feeding roots.

To stimulate new root growth near the center of the rootball, cut out 2 or 3 inch deep V-shaped wedges at the edges of the rootball, from the top of the rootball down to the bottom of the rootball. Cut 4 or 5 wedges out of large rootballs and 2 or 3 wedges out of smaller ones. This procedure not only cuts through circling roots in the rootball, but it also gets rid of some old soil and roots.

The plant can now be returned to the same container. Place the same amount of fresh potting soil at the bottom of the container as was the thickness of the slice of roots that was removed from the bottom of the rootball. Put the plant back into the container, and fill in the V-shaped wedges with fresh potting soil, gently firming it with a stick as you add the soil. Dry soil will flow down easier and fill in the open pockets at the edges of the rootball a lot better than moist soil. The final step is to water the plant well, making sure the dry soil is thoroughly wetted.

After a plant has been root pruned, it has lost a lot of roots, so the plant will need some special care for awhile. Place the plant in a cool, humid room away from bright light, until it has time to develop those new roots. Misting the leaves ocassionally will help conserve water loss from the leaves. Do not water the plant again until the soil is nearly dry - constantly wet soil can cause the cut root ends to rot. Once new growth resumes, the plant may be returned to its original location.

If you feel unsure about this method of root pruning, try it on one of your not so favorite plants. When you see that plant respond and grow with added vigor, because it has so many feeder roots now feeding it, it probably won't be long before you root prune all of your houseplants.

Wintering Dahlia Tubers

Do I have to dig up my Dahlia tubers before winter? If so, when is a good time? Also, what about canna lillies?

Canna x generalis

If the ground freezes in your region, both the dahlias and canna must be dug up and stored overwinter. Dahlias should be dug up as soon as the first hard frost has killed the top growth, otherwise, further severe frost can damage the tubers. Cut the dead stems back to about one inch or so from the tuber. Cut cleanly across any broken part of the tuber with a sharp knife and dust the cut surface with fine sulphur to help prevent the tuber from rotting. The best temperature to store dahlia tubers is between 35 and 55 degrees F. If you do not have a frost-proof root cellar, store them anywhere that is frost proof. In a warm, dry air environment, wrap them in newspaper or cover them with vermiculite, peat moss or sand to help prevent them from shriveling. Check them occassionally in the winter to make sure they are not rotting or shriveling too much.

When you dig up the Cannas (as soon as the leaves have died down), leave as much dirt on the roots as possible. Store them at 45 to 50 degrees F. if possibe. Cover the roots with fine dry soil or sand. In mild climatic regions, cannas may be left in the ground and the soil mulched with several inches of straw, leaves or other material, just in case of a hard frost.